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Integration by parts practice problems

Undo the product rule: ∫u dv = uv − ∫v du. 90 problems with worked solutions; in 82 of them every equation is proved by a computer algebra system.

20 worked problems

Try each one before opening the solution. Every line is labeled with what checked it; 20 of these also have a second solution, written separately and checked the same way. How we verify

Problem 4.168

medium Video
Find \( \displaystyle \int \left(2 x - 1\right) \cos{\left(4 x - 2 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(2 x - 1\right) \cos{\left(4 x - 2 \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(2 x \cos{\left(4 x - 2 \right)} - \cos{\left(4 x - 2 \right)}\right)\, dx \]
    linearityDistribute the cosine term.✓ Proved
  3. \[ = 2 \int x \cos{\left(4 x - 2 \right)}\, dx - \int \cos{\left(4 x - 2 \right)}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = \frac{x \sin{\left(4 x - 2 \right)}}{2} - 2 \int \frac{\sin{\left(4 x - 2 \right)}}{4}\, dx - \int \cos{\left(4 x - 2 \right)}\, dx \]
    parts algebra simplifyApply integration by parts to the first integral, where u = x and dv = cos(4*x - 2)dx. Distribute the 2 into the parentheses. Simplify the coefficient of the first term.✓ Proved
  5. \[ = \frac{x \sin{\left(4 x - 2 \right)}}{2} + \frac{\cos{\left(4 x - 2 \right)}}{8} - \int \cos{\left(4 x - 2 \right)}\, dx \]
    antiderivative algebraIntegrate the sine term. Simplify the sign and fraction.✓ Proved
  6. \[ = \frac{x \sin{\left(4 x - 2 \right)}}{2} - \frac{\sin{\left(4 x - 2 \right)}}{4} + \frac{\cos{\left(4 x - 2 \right)}}{8} \]
    antiderivative simplifyIntegrate the final cosine term. Final simplification of the antiderivative.✓ Proved
Answer \( \frac{x \sin{\left(4 x - 2 \right)}}{2} - \frac{\sin{\left(4 x - 2 \right)}}{4} + \frac{\cos{\left(4 x - 2 \right)}}{8} + C \)
Top: the graph of F = x·sin(4x - 2)/2 - sin(4x - 2)/4 + cos(4x - 2)/8. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (2x - 1)·cos(4x - 2).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(2 x - 1\right) \cos{\left(4 x - 2 \right)}\, dx \]
    integral✓ Proved
  2. \[ = \frac{\int \left(4 x - 2\right) \cos{\left(4 x - 2 \right)}\, dx}{2} \]
    algebraFactor 2*x-1 as (1/2)*(4*x-2)✓ Proved
  3. \[ = \frac{\left(4 x - 2\right) \sin{\left(4 x - 2 \right)}}{8} - \frac{\int \sin{\left(4 x - 2 \right)}\, dx}{2} \]
    partsIntegrate by parts with u=4*x-2, dv=cos(4*x-2)dx✓ Proved
  4. \[ = \frac{\left(4 x - 2\right) \sin{\left(4 x - 2 \right)}}{8} + \frac{\cos{\left(4 x - 2 \right)}}{8} \]
    antiderivative simplifyIntegral of sin(4*x-2) is -cos(4*x-2)/4 Combine constants✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.143

medium Video
Find \( \displaystyle \int \left(2 x - 1\right) e^{1 - 2 x} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(2 x - 1\right) e^{1 - 2 x}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(2 x e^{1 - 2 x} - e^{1 - 2 x}\right)\, dx \]
    linearityDistribute the exponential term.✓ Proved
  3. \[ = 2 \int x e^{1 - 2 x}\, dx - \int e^{1 - 2 x}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = \frac{e^{1 - 2 x}}{2} + 2 \int x e^{1 - 2 x}\, dx \]
    antiderivativeEvaluate the second integral.✓ Proved
  5. \[ = - x e^{1 - 2 x} + \frac{e^{1 - 2 x}}{2} - 2 \int \left(- \frac{e^{1 - 2 x}}{2}\right)\, dx \]
    partsApply integration by parts to the first integral.✓ Proved
  6. \[ = - x e^{1 - 2 x} + \frac{e^{1 - 2 x}}{2} + \int e^{1 - 2 x}\, dx \]
    algebra algebraSimplify the expression inside the parentheses. Distribute the 2.✓ Proved
  7. \[ = - x e^{1 - 2 x} \]
    antiderivative simplifyEvaluate the remaining integral. Combine the terms.✓ Proved
Answer \( - x e^{1 - 2 x} + C \)
Top: the graph of F = -x·e^(1 - 2x). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (2x - 1)·e^(1 - 2x).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(2 x - 1\right) e^{1 - 2 x}\, dx \]
    integral✓ Proved
  2. \[ = \frac{\left(1 - 2 x\right) e^{1 - 2 x}}{2} + \int e^{1 - 2 x}\, dx \]
    partsIntegrate by parts: u=2*x-1, dv=exp(1-2*x)dx✓ Proved
  3. \[ = \frac{\left(1 - 2 x\right) e^{1 - 2 x}}{2} - \frac{e^{1 - 2 x}}{2} \]
    antiderivative∫exp(1-2*x)dx = -exp(1-2*x)/2✓ Proved
  4. \[ = - x e^{1 - 2 x} \]
    simplifyCombine terms✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.153

medium Video
Find \( \displaystyle \int \left(3 x + 1\right) \cos{\left(6 x + 2 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(3 x + 1\right) \cos{\left(6 x + 2 \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(3 x \cos{\left(6 x + 2 \right)} + \cos{\left(6 x + 2 \right)}\right)\, dx \]
    linearityDistribute the cosine term.✓ Proved
  3. \[ = 3 \int x \cos{\left(6 x + 2 \right)}\, dx + \int \cos{\left(6 x + 2 \right)}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = \frac{x \sin{\left(6 x + 2 \right)}}{2} - 3 \int \frac{\sin{\left(6 x + 2 \right)}}{6}\, dx + \int \cos{\left(6 x + 2 \right)}\, dx \]
    partsApply integration by parts to the first integral with u=x and dv=cos(6x+2)dx.✓ Proved
  5. \[ = \frac{x \sin{\left(6 x + 2 \right)}}{2} + \frac{\sin{\left(6 x + 2 \right)}}{6} - 3 \int \frac{\sin{\left(6 x + 2 \right)}}{6}\, dx \]
    antiderivativeEvaluate the integral of cos(6x+2).✓ Proved
  6. \[ = \frac{x \sin{\left(6 x + 2 \right)}}{2} + \frac{\sin{\left(6 x + 2 \right)}}{6} + \frac{\cos{\left(6 x + 2 \right)}}{12} \]
    antiderivative simplify simplifyEvaluate the integral of sin(6x+2). Simplify the expression inside the parentheses. Distribute the 3 and simplify.✓ Proved
  7. \[ = \left(\frac{x}{2} + \frac{1}{6}\right) \sin{\left(6 x + 2 \right)} + \frac{\cos{\left(6 x + 2 \right)}}{12} \]
    simplifyCombine the sine terms.✓ Proved
Answer \( \frac{x \sin{\left(6 x + 2 \right)}}{2} + \frac{\sin{\left(6 x + 2 \right)}}{6} + \frac{\cos{\left(6 x + 2 \right)}}{12} + C \)
Top: the graph of F = x·sin(6x + 2)/2 + sin(6x + 2)/6 + cos(6x + 2)/12. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (3x + 1)·cos(6x + 2).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(3 x + 1\right) \cos{\left(6 x + 2 \right)}\, dx \]
    integral✓ Proved
  2. \[ = \left(\frac{x}{2} + \frac{1}{6}\right) \sin{\left(6 x + 2 \right)} - \int \frac{\sin{\left(6 x + 2 \right)}}{2}\, dx \]
    partsApply integration by parts with u = 3*x+1, dv = cos(6*x+2) dx✓ Proved
  3. \[ = \left(\frac{x}{2} + \frac{1}{6}\right) \sin{\left(6 x + 2 \right)} + \frac{\cos{\left(6 x + 2 \right)}}{12} \]
    antiderivativeIntegrate sin(6*x+2) to get -(1/6)cos(6*x+2)✓ Proved
  4. \[ = \frac{\left(6 x + 2\right) \sin{\left(6 x + 2 \right)}}{12} + \frac{\cos{\left(6 x + 2 \right)}}{12} \]
    simplifyCombine terms over a common denominator✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.156

medium Video
Find \( \displaystyle \int \frac{\ln{\left(x - 1 \right)}}{\left(x - 1\right)^{2}} \, dx \). (Omit the constant of integration.)
  1. \[ \int \frac{\ln{\left(x - 1 \right)}}{\left(x - 1\right)^{2}}\, dx \]
    integral algebraStart with the integral of the given function. Rewrite the denominator using a negative exponent.✓ Proved
  2. \[ = - \int \left(- \frac{1}{\left(x - 1\right)^{2}}\right)\, dx - \frac{\ln{\left(x - 1 \right)}}{x - 1} \]
    parts algebraApply integration by parts with u = log(x - 1) and dv = (x - 1)**(-2) dx. Simplify the integrand of the remaining integral.✓ Proved
  3. \[ = \int \frac{1}{\left(x - 1\right)^{2}}\, dx - \frac{\ln{\left(x - 1 \right)}}{x - 1} \]
    algebraDistribute the negative sign.✓ Proved
  4. \[ = - \frac{\ln{\left(x - 1 \right)}}{x - 1} - \frac{1}{x - 1} \]
    antiderivative algebra algebra simplifyEvaluate the integral of (x - 1)**(-2). Combine the terms by distributing the negative sign. Ensure the expression is simplified. Final simplified form of the antiderivative.✓ Proved
Answer \( \frac{- \ln{\left(x - 1 \right)} - 1}{x - 1} + C \)
Top: the graph of F = (-log(x - 1) - 1)/(x - 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = log(x - 1)/(x - 1)².
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \frac{\ln{\left(x - 1 \right)}}{\left(x - 1\right)^{2}}\, dx \]
    integral✓ Proved
  2. \[ = \int \frac{1}{\left(x - 1\right)^{2}}\, dx - \frac{\ln{\left(x - 1 \right)}}{x - 1} \]
    partsIntegration by parts: u=log(x-1), dv=1/(x-1)**2 dx✓ Proved
  3. \[ = - \frac{\ln{\left(x - 1 \right)}}{x - 1} - \frac{1}{x - 1} \]
    antiderivativeIntegral of 1/(x-1)**2 is -1/(x-1)✓ Proved
  4. \[ = \frac{- \ln{\left(x - 1 \right)} - 1}{x - 1} \]
    simplifyCombine terms over common denominator✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.560

medium Video
Find \( \displaystyle \int 9 x^{2} e^{3 x} \, dx \). (Omit the constant of integration.)
  1. \[ \int 9 x^{2} e^{3 x}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = 9 \int x^{2} e^{3 x}\, dx \]
    linearityFactor out the constant 9.✓ Proved
  3. \[ = 3 x^{2} e^{3 x} - 3 \int 2 x e^{3 x}\, dx \]
    parts algebraApply integration by parts with u = x**2 and dv = exp(3*x)dx. Distribute the 9 and simplify the fraction.✓ Proved
  4. \[ = 3 x^{2} e^{3 x} - 6 \int x e^{3 x}\, dx \]
    algebraFactor out the 2 from the integral.✓ Proved
  5. \[ = 3 x^{2} e^{3 x} - 2 x e^{3 x} + 2 \int e^{3 x}\, dx \]
    parts algebraApply integration by parts to the remaining integral with u = x and dv = exp(3*x)dx. Distribute the -6 and simplify the terms.✓ Proved
  6. \[ = 3 x^{2} e^{3 x} - 2 x e^{3 x} + \frac{2 e^{3 x}}{3} \]
    antiderivativeEvaluate the final integral.✓ Proved
  7. \[ = \left(3 x^{2} - 2 x + \frac{2}{3}\right) e^{3 x} \]
    simplifyFactor out the common exponential term.✓ Proved
Answer \( \frac{\left(9 x^{2} - 6 x + 2\right) e^{3 x}}{3} + C \)
Top: the graph of F = (9x² - 6x + 2)·e^(3x)/3. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = 9x²·e^(3x).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int 9 x^{2} e^{3 x}\, dx \]
    integral✓ Proved
  2. \[ = 3 x^{2} e^{3 x} - \int 6 x e^{3 x}\, dx \]
    partsFirst integration by parts: u=x**2, dv=9*exp(3*x)dx✓ Proved
  3. \[ = 3 x^{2} e^{3 x} - 2 x e^{3 x} + \int 2 e^{3 x}\, dx \]
    partsSecond integration by parts: u=x, dv=6*exp(3*x)dx✓ Proved
  4. \[ = 3 x^{2} e^{3 x} - 2 x e^{3 x} + \frac{2 e^{3 x}}{3} \]
    simplifyIntegrate the remaining exponential and combine terms✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.729

medium Video
Find \( \displaystyle \int \left(3 x + 1\right)^{2} e^{3 x + 1} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(3 x + 1\right)^{2} e^{3 x + 1}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(9 x^{2} + 6 x + 1\right) e^{3 x + 1}\, dx \]
    algebraExpand the squared binomial.✓ Proved
  3. \[ = 6 \int x e^{3 x + 1}\, dx + 9 \int x^{2} e^{3 x + 1}\, dx + \int e^{3 x + 1}\, dx \]
    linearityDistribute the exponential term and split the integral into three parts.✓ Proved
  4. \[ = \frac{e^{3 x + 1}}{3} + 6 \int x e^{3 x + 1}\, dx + 9 \int x^{2} e^{3 x + 1}\, dx \]
    antiderivativeEvaluate the integral of the constant term.✓ Proved
  5. \[ = 3 x^{2} e^{3 x + 1} + \frac{e^{3 x + 1}}{3} - 9 \int \frac{2 x e^{3 x + 1}}{3}\, dx + 6 \int x e^{3 x + 1}\, dx \]
    partsApply integration by parts to the first integral term.✓ Proved
  6. \[ = 3 x^{2} e^{3 x + 1} + \frac{e^{3 x + 1}}{3} \]
    simplify algebra simplifySimplify the expression inside the parentheses. Distribute the 9 into the parentheses. Cancel the remaining integral terms.✓ Proved
  7. \[ = \left(3 x^{2} + \frac{1}{3}\right) e^{3 x + 1} \]
    algebraFactor out the exponential term.✓ Proved
Answer \( \frac{\left(9 x^{2} + 1\right) e^{3 x + 1}}{3} + C \)
Top: the graph of F = (9x² + 1)·e^(3x + 1)/3. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (3x + 1)²·e^(3x + 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(3 x + 1\right)^{2} e^{3 x + 1}\, dx \]
    integral✓ Proved
  2. \[ = \frac{\left(3 x + 1\right)^{2} e^{3 x + 1}}{3} - \int \left(6 x + 2\right) e^{3 x + 1}\, dx \]
    partsApply integration by parts once✓ Proved
  3. \[ = \frac{\left(3 x + 1\right)^{2} e^{3 x + 1}}{3} - \frac{2 \left(3 x + 1\right) e^{3 x + 1}}{3} + 2 \int e^{3 x + 1}\, dx \]
    partsApply integration by parts to the remaining integral✓ Proved
  4. \[ = \frac{\left(3 x + 1\right)^{2} e^{3 x + 1}}{3} - \frac{\left(6 x + 2\right) e^{3 x + 1}}{3} + 2 \int e^{3 x + 1}\, dx \]
    simplifyDistribute the factor 2 and simplify✓ Proved
  5. \[ = \frac{\left(3 x + 1\right)^{2} e^{3 x + 1}}{3} - \frac{\left(6 x + 2\right) e^{3 x + 1}}{3} + \frac{2 e^{3 x + 1}}{3} \]
    antiderivativeIntegrate exp(3*x + 1)✓ Proved
  6. \[ = \frac{\left(- 6 x + \left(3 x + 1\right)^{2}\right) e^{3 x + 1}}{3} \]
    simplifyFactor out exp(3*x + 1)/3✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.732

medium Video
Find \( \displaystyle \int 2 x \ln{\left(2 x \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int 2 x \ln{\left(2 x \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int 2 x \left(\ln{\left(x \right)} + \ln{\left(2 \right)}\right)\, dx \]
    algebraUse the logarithm product rule to expand the integrand.✓ Proved
  3. \[ = 2 \ln{\left(2 \right)} \int x\, dx + 2 \int x \ln{\left(x \right)}\, dx \]
    linearityDistribute the 2*x and split the integral into two parts.✓ Proved
  4. \[ = x^{2} \ln{\left(2 \right)} + 2 \int x \ln{\left(x \right)}\, dx \]
    antiderivativeIntegrate the first term.✓ Proved
  5. \[ = x^{2} \ln{\left(x \right)} + x^{2} \ln{\left(2 \right)} - 2 \int \frac{x}{2}\, dx \]
    parts algebra algebraApply integration by parts to the second integral with u=log(x) and dv=x dx. Simplify the integrand inside the integral. Distribute the 2 into the parentheses.✓ Proved
  6. \[ = x^{2} \ln{\left(x \right)} - \frac{x^{2}}{2} + x^{2} \ln{\left(2 \right)} \]
    antiderivative simplifyIntegrate the remaining term. Simplify the final expression.✓ Proved
Answer \( x^{2} \left(\ln{\left(2 x \right)} - \frac{1}{2}\right) + C \)
Top: the graph of F = x²·(log(2x) - 1/2). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = 2x·log(2x).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int 2 x \ln{\left(2 x \right)}\, dx \]
    integral✓ Proved
  2. \[ = \int 2 x \left(\ln{\left(x \right)} + \ln{\left(2 \right)}\right)\, dx \]
    rewriteUse log(a*b)=log(a)+log(b)✓ Proved
  3. \[ = \int 2 x \ln{\left(2 \right)}\, dx + \int 2 x \ln{\left(x \right)}\, dx \]
    linearitySplit the integral✓ Proved
  4. \[ = x^{2} \ln{\left(2 \right)} + \int 2 x \ln{\left(x \right)}\, dx \]
    antiderivativeIntegrate 2*x*log(2)✓ Proved
  5. \[ = x^{2} \ln{\left(x \right)} + x^{2} \ln{\left(2 \right)} - \int x\, dx \]
    partsIntegrate 2*x*log(x) by parts✓ Proved
  6. \[ = x^{2} \ln{\left(x \right)} - \frac{x^{2}}{2} + x^{2} \ln{\left(2 \right)} \]
    antiderivativeIntegrate x✓ Proved
  7. \[ = x^{2} \left(\ln{\left(x \right)} - \frac{1}{2} + \ln{\left(2 \right)}\right) \]
    simplifyCombine terms✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.1407

medium Video
Find \( \displaystyle \int \left(2 x + 1\right) e^{- 2 x - 1} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(2 x + 1\right) e^{- 2 x - 1}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(2 x e^{- 2 x - 1} + e^{- 2 x - 1}\right)\, dx \]
    linearityDistribute the exponential term.✓ Proved
  3. \[ = 2 \int x e^{- 2 x - 1}\, dx + \int e^{- 2 x - 1}\, dx \]
    linearitySplit into two integrals.✓ Proved
  4. \[ = - x e^{- 2 x - 1} - 2 \int \left(- \frac{e^{- 2 x - 1}}{2}\right)\, dx + \int e^{- 2 x - 1}\, dx \]
    partsApply integration by parts to the first integral with u=x and dv=exp(-2*x-1)dx.✓ Proved
  5. \[ = - x e^{- 2 x - 1} + 2 \int e^{- 2 x - 1}\, dx \]
    algebra algebra algebraSimplify the sign inside the parentheses. Distribute the constant 2. Combine the integral terms.✓ Proved
  6. \[ = - x e^{- 2 x - 1} - e^{- 2 x - 1} \]
    antiderivative algebraEvaluate the remaining integral. Simplify the final expression.✓ Proved
Answer \( \left(- x - 1\right) e^{- 2 x - 1} + C \)
Top: the graph of F = (-x - 1)·e^(-2x - 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (2x + 1)·e^(-2x - 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(2 x + 1\right) e^{- 2 x - 1}\, dx \]
    integral✓ Proved
  2. \[ = \frac{\left(- 2 x - 1\right) e^{- 2 x - 1}}{2} + \int e^{- 2 x - 1}\, dx \]
    parts✓ Proved
  3. \[ = \frac{\left(- 2 x - 1\right) e^{- 2 x - 1}}{2} - \frac{e^{- 2 x - 1}}{2} \]
    antiderivative✓ Proved
  4. \[ = \left(- x - 1\right) e^{- 2 x - 1} \]
    simplify✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.151

medium Video
Find \( \displaystyle \int 9 x^{2} \sin{\left(3 x \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int 9 x^{2} \sin{\left(3 x \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = 9 \int x^{2} \sin{\left(3 x \right)}\, dx \]
    linearityPull out the constant factor 9.✓ Proved
  3. \[ = - 3 x^{2} \cos{\left(3 x \right)} + 9 \int \frac{2 x \cos{\left(3 x \right)}}{3}\, dx \]
    partsApply integration by parts with u = x**2 and dv = sin(3*x)dx.✓ Proved
  4. \[ = - 3 x^{2} \cos{\left(3 x \right)} + 6 \int x \cos{\left(3 x \right)}\, dx \]
    algebraSimplify the expression inside the integral.✓ Proved
  5. \[ = - 3 x^{2} \cos{\left(3 x \right)} + 2 x \sin{\left(3 x \right)} - 6 \int \frac{\sin{\left(3 x \right)}}{3}\, dx \]
    partsApply integration by parts again to the remaining integral.✓ Proved
  6. \[ = - 3 x^{2} \cos{\left(3 x \right)} + 2 x \sin{\left(3 x \right)} - 2 \int \sin{\left(3 x \right)}\, dx \]
    algebraDistribute the 2/3 factor.✓ Proved
  7. \[ = - 3 x^{2} \cos{\left(3 x \right)} + 2 x \sin{\left(3 x \right)} + \frac{2 \cos{\left(3 x \right)}}{3} \]
    antiderivative simplifyEvaluate the integral of sin(3*x). Distribute the 9 and simplify the terms.✓ Proved
Answer \( - 3 x^{2} \cos{\left(3 x \right)} + 2 x \sin{\left(3 x \right)} + \frac{2 \cos{\left(3 x \right)}}{3} + C \)
Top: the graph of F = -3x²·cos(3x) + 2x·sin(3x) + 2cos(3x)/3. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = 9x²·sin(3x).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int 9 x^{2} \sin{\left(3 x \right)}\, dx \]
    integral✓ Proved
  2. \[ = - 3 x^{2} \cos{\left(3 x \right)} + \int 6 x \cos{\left(3 x \right)}\, dx \]
    partsFirst integration by parts: u=x**2, dv=9*sin(3*x)dx✓ Proved
  3. \[ = - 3 x^{2} \cos{\left(3 x \right)} + 2 x \sin{\left(3 x \right)} - \int 2 \sin{\left(3 x \right)}\, dx \]
    partsSecond integration by parts: u=6*x, dv=cos(3*x)dx✓ Proved
  4. \[ = - 3 x^{2} \cos{\left(3 x \right)} + 2 x \sin{\left(3 x \right)} + \frac{2 \cos{\left(3 x \right)}}{3} \]
    antiderivativeIntegrate the remaining sin term✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.157

medium Video
Find \( \displaystyle \int \left(x - 1\right) \cos{\left(x - 1 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(x - 1\right) \cos{\left(x - 1 \right)}\, dx \]
    integralStart with the given integral.✓ Proved
  2. \[ = \int \left(x \cos{\left(x - 1 \right)} - \cos{\left(x - 1 \right)}\right)\, dx \]
    algebraDistribute the cosine term.✓ Proved
  3. \[ = \int x \cos{\left(x - 1 \right)}\, dx - \int \cos{\left(x - 1 \right)}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = - \sin{\left(x - 1 \right)} + \int x \cos{\left(x - 1 \right)}\, dx \]
    antiderivativeIntegrate the second term.✓ Proved
  5. \[ = x \sin{\left(x - 1 \right)} - \sin{\left(x - 1 \right)} - \int \sin{\left(x - 1 \right)}\, dx \]
    partsApply integration by parts to the first term with u=x and dv=cos(x-1)dx.✓ Proved
  6. \[ = x \sin{\left(x - 1 \right)} - \sin{\left(x - 1 \right)} + \cos{\left(x - 1 \right)} \]
    antiderivative algebraIntegrate the remaining sine term. Simplify the signs.✓ Proved
  7. \[ = \left(x - 1\right) \sin{\left(x - 1 \right)} + \cos{\left(x - 1 \right)} \]
    simplifyFactor out the sine term.✓ Proved
Answer \( x \sin{\left(x - 1 \right)} - \sin{\left(x - 1 \right)} + \cos{\left(x - 1 \right)} + C \)
Top: the graph of F = x·sin(x - 1) - sin(x - 1) + cos(x - 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (x - 1)·cos(x - 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(x - 1\right) \cos{\left(x - 1 \right)}\, dx \]
    integral✓ Proved
  2. \[ = \left(x - 1\right) \sin{\left(x - 1 \right)} - \int \sin{\left(x - 1 \right)}\, dx \]
    partsApply integration by parts with u = x-1, dv = cos(x-1)dx✓ Proved
  3. \[ = \left(x - 1\right) \sin{\left(x - 1 \right)} + \cos{\left(x - 1 \right)} \]
    antiderivativeIntegrate sin(x-1) to get -cos(x-1) and simplify✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.163

medium Video
Find \( \displaystyle \int \left(x + 1\right) \cos{\left(x + 1 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(x + 1\right) \cos{\left(x + 1 \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(x \cos{\left(x + 1 \right)} + \cos{\left(x + 1 \right)}\right)\, dx \]
    algebraDistribute the term (x + 1) into the cosine.✓ Proved
  3. \[ = \int x \cos{\left(x + 1 \right)}\, dx + \int \cos{\left(x + 1 \right)}\, dx \]
    linearitySplit the integral into two separate integrals.✓ Proved
  4. \[ = \sin{\left(x + 1 \right)} + \int x \cos{\left(x + 1 \right)}\, dx \]
    antiderivativeIntegrate the second term cos(x + 1).✓ Proved
  5. \[ = x \sin{\left(x + 1 \right)} + \sin{\left(x + 1 \right)} - \int \sin{\left(x + 1 \right)}\, dx \]
    partsApply integration by parts to the first term with u = x and dv = cos(x + 1)dx.✓ Proved
  6. \[ = x \sin{\left(x + 1 \right)} + \sin{\left(x + 1 \right)} + \cos{\left(x + 1 \right)} \]
    antiderivative algebraIntegrate sin(x + 1). Simplify the signs.✓ Proved
  7. \[ = \left(x + 1\right) \sin{\left(x + 1 \right)} + \cos{\left(x + 1 \right)} \]
    algebraFactor out sin(x + 1) to get the final form.✓ Proved
Answer \( x \sin{\left(x + 1 \right)} + \sin{\left(x + 1 \right)} + \cos{\left(x + 1 \right)} + C \)
Top: the graph of F = x·sin(x + 1) + sin(x + 1) + cos(x + 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (x + 1)·cos(x + 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(x + 1\right) \cos{\left(x + 1 \right)}\, dx \]
    integral✓ Proved
  2. \[ = \left(x + 1\right) \sin{\left(x + 1 \right)} - \int \sin{\left(x + 1 \right)}\, dx \]
    partsIntegrate by parts with u = x+1, dv = cos(x+1)dx✓ Proved
  3. \[ = \left(x + 1\right) \sin{\left(x + 1 \right)} + \cos{\left(x + 1 \right)} \]
    antiderivative∫ sin(x+1) dx = -cos(x+1)✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.169

medium Video
Find \( \displaystyle \int \left(3 x - 1\right) e^{3 x - 1} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(3 x - 1\right) e^{3 x - 1}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(3 x e^{3 x - 1} - e^{3 x - 1}\right)\, dx \]
    linearityDistribute the exponential term.✓ Proved
  3. \[ = 3 \int x e^{3 x - 1}\, dx - \int e^{3 x - 1}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = x e^{3 x - 1} - 3 \int \frac{e^{3 x - 1}}{3}\, dx - \int e^{3 x - 1}\, dx \]
    partsApply integration by parts to the first integral term.✓ Proved
  5. \[ = x e^{3 x - 1} - 2 \int e^{3 x - 1}\, dx \]
    simplify algebraSimplify the expression. Combine the integral terms.✓ Proved
  6. \[ = x e^{3 x - 1} - \frac{2 e^{3 x - 1}}{3} \]
    antiderivative simplifyEvaluate the remaining integral. Final simplification.✓ Proved
Answer \( \left(x - \frac{2}{3}\right) e^{3 x - 1} + C \)
Top: the graph of F = (x - 2/3)·e^(3x - 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (3x - 1)·e^(3x - 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(3 x - 1\right) e^{3 x - 1}\, dx \]
    integral✓ Proved
  2. \[ = \frac{\left(3 x - 1\right) e^{3 x - 1}}{3} - \int e^{3 x - 1}\, dx \]
    partsApply integration by parts with u=3*x-1, dv=exp(3*x-1)dx✓ Proved
  3. \[ = \frac{\left(3 x - 1\right) e^{3 x - 1}}{3} - \frac{e^{3 x - 1}}{3} \]
    antiderivativeIntegrate exp(3*x-1) to get exp(3*x-1)/3✓ Proved
  4. \[ = \frac{\left(3 x - 2\right) e^{3 x - 1}}{3} \]
    simplifyCombine terms✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.801

medium Video
Find \( \displaystyle \int 4 x^{2} \ln{\left(2 x \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int 4 x^{2} \ln{\left(2 x \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int 4 x^{2} \left(\ln{\left(x \right)} + \ln{\left(2 \right)}\right)\, dx \]
    algebraUse the logarithm product rule to split the log term.✓ Proved
  3. \[ = 4 \ln{\left(2 \right)} \int x^{2}\, dx + 4 \int x^{2} \ln{\left(x \right)}\, dx \]
    linearityDistribute the term and split into two integrals.✓ Proved
  4. \[ = \frac{4 x^{3} \ln{\left(2 \right)}}{3} + 4 \int x^{2} \ln{\left(x \right)}\, dx \]
    antiderivativeEvaluate the first simple integral.✓ Proved
  5. \[ = \frac{4 x^{3} \ln{\left(x \right)}}{3} + \frac{4 x^{3} \ln{\left(2 \right)}}{3} - 4 \int \frac{x^{2}}{3}\, dx \]
    parts algebraUse integration by parts on the second integral with u=log(x) and dv=x**2 dx. Simplify the integrand inside the integral.✓ Proved
  6. \[ = \frac{4 x^{3} \ln{\left(x \right)}}{3} - \frac{4 x^{3}}{9} + \frac{4 x^{3} \ln{\left(2 \right)}}{3} \]
    antiderivative simplifyEvaluate the remaining power rule integral. Distribute the constants and simplify the expression.✓ Proved
Answer \( \frac{4 x^{3} \left(3 \ln{\left(2 x \right)} - 1\right)}{9} + C \)
Top: the graph of F = 4x³·(3log(2x) - 1)/9. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = 4x²·log(2x).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int 4 x^{2} \ln{\left(2 x \right)}\, dx \]
    integral✓ Proved
  2. \[ = \int 4 x^{2} \left(\ln{\left(x \right)} + \ln{\left(2 \right)}\right)\, dx \]
    rewriteUse log(ab)=log(a)+log(b)✓ Proved
  3. \[ = 4 \ln{\left(2 \right)} \int x^{2}\, dx + \int 4 x^{2} \ln{\left(x \right)}\, dx \]
    linearitySplit the integral✓ Proved
  4. \[ = \frac{4 x^{3} \ln{\left(2 \right)}}{3} + \int 4 x^{2} \ln{\left(x \right)}\, dx \]
    antiderivativeIntegrate x**2✓ Proved
  5. \[ = \frac{4 x^{3} \ln{\left(x \right)}}{3} + \frac{4 x^{3} \ln{\left(2 \right)}}{3} - \int \frac{4 x^{2}}{3}\, dx \]
    partsIntegrate by parts on the remaining integral✓ Proved
  6. \[ = \frac{4 x^{3} \ln{\left(x \right)}}{3} - \frac{4 x^{3}}{9} + \frac{4 x^{3} \ln{\left(2 \right)}}{3} \]
    antiderivativeIntegrate the remaining x**2 term✓ Proved
  7. \[ = \frac{4 x^{3} \ln{\left(2 x \right)}}{3} - \frac{4 x^{3}}{9} \]
    simplifyCombine logs✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.141

medium Video
Find \( \displaystyle \int 2 x \cos{\left(4 x \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int 2 x \cos{\left(4 x \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = 2 \int x \cos{\left(4 x \right)}\, dx \]
    linearityFactor out the constant 2.✓ Proved
  3. \[ = \frac{x \sin{\left(4 x \right)}}{2} - 2 \int \frac{\sin{\left(4 x \right)}}{4}\, dx \]
    parts algebraApply integration by parts with u = x and dv = cos(4*x)dx. Distribute the x into the first term.✓ Proved
  4. \[ = \frac{x \sin{\left(4 x \right)}}{2} + \frac{\cos{\left(4 x \right)}}{8} \]
    antiderivative algebra simplifyEvaluate the integral of sin(4*x)/4. Simplify the signs and the denominator. Distribute the 2 and simplify the expression.✓ Proved
Answer \( \frac{x \sin{\left(4 x \right)}}{2} + \frac{\cos{\left(4 x \right)}}{8} + C \)
Top: the graph of F = x·sin(4x)/2 + cos(4x)/8. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = 2x·cos(4x).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int 2 x \cos{\left(4 x \right)}\, dx \]
    integral✓ Proved
  2. \[ = \frac{x \sin{\left(4 x \right)}}{2} - \int \frac{\sin{\left(4 x \right)}}{2}\, dx \]
    partsIntegrate by parts: u=2*x, dv=cos(4*x)dx✓ Proved
  3. \[ = \frac{x \sin{\left(4 x \right)}}{2} + \frac{\cos{\left(4 x \right)}}{8} \]
    antiderivative∫ sin(4*x)/2 dx = -cos(4*x)/8, subtracting gives +cos(4*x)/8✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.370

medium Video
Find \( \displaystyle \int \left(x + 1\right) \sin{\left(x + 1 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(x + 1\right) \sin{\left(x + 1 \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(x \sin{\left(x + 1 \right)} + \sin{\left(x + 1 \right)}\right)\, dx \]
    algebraDistribute the (x + 1) term.✓ Proved
  3. \[ = \int x \sin{\left(x + 1 \right)}\, dx + \int \sin{\left(x + 1 \right)}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = - x \cos{\left(x + 1 \right)} + \int \sin{\left(x + 1 \right)}\, dx + \int \cos{\left(x + 1 \right)}\, dx \]
    partsApply integration by parts to the first integral with u = x and dv = sin(x + 1)dx.✓ Proved
  5. \[ = - x \cos{\left(x + 1 \right)} + \sin{\left(x + 1 \right)} + \int \sin{\left(x + 1 \right)}\, dx \]
    antiderivativeEvaluate the integral of cos(x + 1).✓ Proved
  6. \[ = - x \cos{\left(x + 1 \right)} + \sin{\left(x + 1 \right)} - \cos{\left(x + 1 \right)} \]
    antiderivative simplifyEvaluate the remaining integral of sin(x + 1). Rearrange the terms.✓ Proved
Answer \( - x \cos{\left(x + 1 \right)} + \sin{\left(x + 1 \right)} - \cos{\left(x + 1 \right)} + C \)
Top: the graph of F = -x·cos(x + 1) + sin(x + 1) - cos(x + 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (x + 1)·sin(x + 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(x + 1\right) \sin{\left(x + 1 \right)}\, dx \]
    integral✓ Proved
  2. \[ = \left(- x - 1\right) \cos{\left(x + 1 \right)} + \int \cos{\left(x + 1 \right)}\, dx \]
    partsIntegrate by parts: u = x+1, dv = sin(x+1)dx✓ Proved
  3. \[ = \left(- x - 1\right) \cos{\left(x + 1 \right)} + \sin{\left(x + 1 \right)} \]
    antiderivativeIntegral of cos(x+1) is sin(x+1)✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.656

medium Video
Find \( \displaystyle \int \left(2 x + 1\right) e^{2 x + 1} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(2 x + 1\right) e^{2 x + 1}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(2 x e^{2 x + 1} + e^{2 x + 1}\right)\, dx \]
    linearityDistribute the exponential term.✓ Proved
  3. \[ = \int 2 x e^{2 x + 1}\, dx + \int e^{2 x + 1}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = \frac{e^{2 x + 1}}{2} + \int 2 x e^{2 x + 1}\, dx \]
    antiderivativeIntegrate the second term.✓ Proved
  5. \[ = x e^{2 x + 1} + \frac{e^{2 x + 1}}{2} - \int e^{2 x + 1}\, dx \]
    partsApply integration by parts to the first term with u=x and dv=2*exp(2*x+1)dx.✓ Proved
  6. \[ = x e^{2 x + 1} \]
    antiderivative simplifyIntegrate the remaining exponential term. Combine the terms.✓ Proved
Answer \( x e^{2 x + 1} + C \)
Top: the graph of F = x·e^(2x + 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (2x + 1)·e^(2x + 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(2 x + 1\right) e^{2 x + 1}\, dx \]
    integral✓ Proved
  2. \[ = \left(x + \frac{1}{2}\right) e^{2 x + 1} - \int e^{2 x + 1}\, dx \]
    parts✓ Proved
  3. \[ = \frac{\left(2 x + 1\right) e^{2 x + 1}}{2} + \int \left(- e^{2 x + 1}\right)\, dx \]
    rewriteRewrite the integral with a negative sign✓ Proved
  4. \[ = \frac{\left(2 x + 1\right) e^{2 x + 1}}{2} - \frac{e^{2 x + 1}}{2} \]
    antiderivative✓ Proved
  5. \[ = x e^{2 x + 1} \]
    simplify✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.999

medium Video
Find \( \displaystyle \int \left(x - 1\right)^{2} \ln{\left(x - 1 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(x - 1\right)^{2} \ln{\left(x - 1 \right)}\, dx \]
    integral simplify partsStart with the integral of the given function. The integrand is already in its simplest form. Use integration by parts with u = log(x - 1) and dv = (x - 1)**2 dx.✓ Proved
  2. \[ = \frac{\left(x - 1\right)^{3} \ln{\left(x - 1 \right)}}{3} - \int \frac{\left(x - 1\right)^{2}}{3}\, dx \]
    parts algebraApply the integration by parts formula: integral(u dv) = uv - integral(v du). Simplify the integrand in the second term.✓ Proved
  3. \[ = \frac{\left(x - 1\right)^{3} \ln{\left(x - 1 \right)}}{3} - \frac{\left(x - 1\right)^{3}}{9} \]
    antiderivative simplifyIntegrate the power function. Simplify the expression.✓ Proved
Answer \( - \frac{x^{3}}{9} + \frac{x^{2}}{3} - \frac{x}{3} + \left(\frac{x^{3}}{3} - x^{2} + x\right) \ln{\left(x - 1 \right)} - \frac{\ln{\left(x - 1 \right)}}{3} + C \)
Top: the graph of F = -x³/9 + x²/3 - x/3 + (x³/3 - x² + x)·log(x - 1) - log(x - 1)/3. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (x - 1)²·log(x - 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(x - 1\right)^{2} \ln{\left(x - 1 \right)}\, dx \]
    integral✓ Proved
  2. \[ = \frac{\left(x - 1\right)^{3} \ln{\left(x - 1 \right)}}{3} - \int \frac{\left(x - 1\right)^{2}}{3}\, dx \]
    partsIntegrate by parts with u=log(x-1), dv=(x-1)**2 dx✓ Proved
  3. \[ = \frac{\left(x - 1\right)^{3} \ln{\left(x - 1 \right)}}{3} - \frac{\left(x - 1\right)^{3}}{9} \]
    antiderivativeIntegrate (x-1)**2/3 to get (x-1)**3/9✓ Proved
  4. \[ = \frac{\left(x - 1\right)^{3} \left(3 \ln{\left(x - 1 \right)} - 1\right)}{9} \]
    simplifyCombine terms✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.1320

medium Video
Find \( \displaystyle \int \left(2 x + 1\right) \sin{\left(2 x + 1 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(2 x + 1\right) \sin{\left(2 x + 1 \right)}\, dx \]
    integralStart with the integral of the integrand.✓ Proved
  2. \[ = - \frac{\left(2 x + 1\right) \cos{\left(2 x + 1 \right)}}{2} - \int \left(- \cos{\left(2 x + 1 \right)}\right)\, dx \]
    parts algebraApply integration by parts with u = 2*x + 1 and dv = sin(2*x + 1) dx. Simplify the integrand in the remaining integral.✓ Proved
  3. \[ = - \frac{\left(2 x + 1\right) \cos{\left(2 x + 1 \right)}}{2} + \int \cos{\left(2 x + 1 \right)}\, dx \]
    algebraDistribute the negative sign.✓ Proved
  4. \[ = - \frac{\left(2 x + 1\right) \cos{\left(2 x + 1 \right)}}{2} + \frac{\sin{\left(2 x + 1 \right)}}{2} \]
    antiderivativeIntegrate the remaining cosine term.✓ Proved
  5. \[ = \frac{\left(- 2 x - 1\right) \cos{\left(2 x + 1 \right)}}{2} + \frac{\sin{\left(2 x + 1 \right)}}{2} \]
    algebraDistribute the fraction.✓ Proved
  6. \[ = - x \cos{\left(2 x + 1 \right)} + \frac{\sin{\left(2 x + 1 \right)}}{2} - \frac{\cos{\left(2 x + 1 \right)}}{2} \]
    algebraExpand the expression.✓ Proved
Answer \( - x \cos{\left(2 x + 1 \right)} + \frac{\sin{\left(2 x + 1 \right)}}{2} - \frac{\cos{\left(2 x + 1 \right)}}{2} + C \)
Top: the graph of F = -x·cos(2x + 1) + sin(2x + 1)/2 - cos(2x + 1)/2. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (2x + 1)·sin(2x + 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(2 x + 1\right) \sin{\left(2 x + 1 \right)}\, dx \]
    integral✓ Proved
  2. \[ = - \frac{\left(2 x + 1\right) \cos{\left(2 x + 1 \right)}}{2} - \int \left(- \cos{\left(2 x + 1 \right)}\right)\, dx \]
    partsApply integration by parts with u = 2*x+1, dv = sin(2*x+1)dx✓ Proved
  3. \[ = \frac{\left(- 2 x - 1\right) \cos{\left(2 x + 1 \right)}}{2} + \int \cos{\left(2 x + 1 \right)}\, dx \]
    simplifySimplify the product inside the integral✓ Proved
  4. \[ = \frac{\left(- 2 x - 1\right) \cos{\left(2 x + 1 \right)}}{2} + \frac{\sin{\left(2 x + 1 \right)}}{2} \]
    antiderivativeIntegrate cos(2*x+1) to get sin(2*x+1)/2✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.158

medium Video
Find \( \displaystyle \int \left(x - 1\right) \sin{\left(x - 1 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(x - 1\right) \sin{\left(x - 1 \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \left(x \sin{\left(x - 1 \right)} - \sin{\left(x - 1 \right)}\right)\, dx \]
    algebraDistribute the term (x - 1).✓ Proved
  3. \[ = \int x \sin{\left(x - 1 \right)}\, dx - \int \sin{\left(x - 1 \right)}\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  4. \[ = - x \cos{\left(x - 1 \right)} - \int \sin{\left(x - 1 \right)}\, dx + \int \cos{\left(x - 1 \right)}\, dx \]
    partsApply integration by parts to the first integral with u = x and dv = sin(x - 1)dx.✓ Proved
  5. \[ = - x \cos{\left(x - 1 \right)} + \int \left(- \sin{\left(x - 1 \right)} + \cos{\left(x - 1 \right)}\right)\, dx \]
    linearityCombine the remaining integrals.✓ Proved
  6. \[ = - x \cos{\left(x - 1 \right)} + \sin{\left(x - 1 \right)} + \cos{\left(x - 1 \right)} \]
    antiderivativeEvaluate the remaining integrals.✓ Proved
Answer \( - x \cos{\left(x - 1 \right)} + \sin{\left(x - 1 \right)} + \cos{\left(x - 1 \right)} + C \)
Top: the graph of F = -x·cos(x - 1) + sin(x - 1) + cos(x - 1). A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (x - 1)·sin(x - 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(x - 1\right) \sin{\left(x - 1 \right)}\, dx \]
    integral✓ Proved
  2. \[ = \left(1 - x\right) \cos{\left(x - 1 \right)} + \int \cos{\left(x - 1 \right)}\, dx \]
    partsIntegrate by parts with u = x-1, dv = sin(x-1)dx.✓ Proved
  3. \[ = \left(1 - x\right) \cos{\left(x - 1 \right)} + \sin{\left(x - 1 \right)} \]
    antiderivativeIntegral of cos(x-1) is sin(x-1).✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

Problem 4.161

medium Video
Find \( \displaystyle \int \left(2 x - 1\right) \sin{\left(2 x - 1 \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(2 x - 1\right) \sin{\left(2 x - 1 \right)}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = - \frac{\left(2 x - 1\right) \cos{\left(2 x - 1 \right)}}{2} - \int \left(- \cos{\left(2 x - 1 \right)}\right)\, dx \]
    partsApply integration by parts with u = 2*x - 1 and dv = sin(2*x - 1) dx.✓ Proved
  3. \[ = - \frac{\left(2 x - 1\right) \cos{\left(2 x - 1 \right)}}{2} + \int \cos{\left(2 x - 1 \right)}\, dx \]
    algebraSimplify the integrand in the remaining integral.✓ Proved
  4. \[ = - \frac{\left(2 x - 1\right) \cos{\left(2 x - 1 \right)}}{2} + \frac{\sin{\left(2 x - 1 \right)}}{2} \]
    antiderivativeEvaluate the integral of cos(2*x - 1).✓ Proved
  5. \[ = - x \cos{\left(2 x - 1 \right)} + \frac{\sin{\left(2 x - 1 \right)}}{2} + \frac{\cos{\left(2 x - 1 \right)}}{2} \]
    algebraDistribute the terms and simplify.✓ Proved
  6. \[ = \left(\frac{1}{2} - x\right) \cos{\left(2 x - 1 \right)} + \frac{\sin{\left(2 x - 1 \right)}}{2} \]
    simplifyCombine the cosine terms.✓ Proved
Answer \( - x \cos{\left(2 x - 1 \right)} + \frac{\sin{\left(2 x - 1 \right)}}{2} + \frac{\cos{\left(2 x - 1 \right)}}{2} + C \)
Top: the graph of F = -x·cos(2x - 1) + sin(2x - 1)/2 + cos(2x - 1)/2. A tangent line slides along it, and its slope is plotted below as it goes, tracing f = (2x - 1)·sin(2x - 1).
A second solution, written separately

By gpt-oss:20b, without seeing the first. SymPy checked every line.

  1. \[ \int \left(2 x - 1\right) \sin{\left(2 x - 1 \right)}\, dx \]
    integralStart with the given integral.✓ Proved
  2. \[ = \frac{\left(1 - 2 x\right) \cos{\left(2 x - 1 \right)}}{2} + \int \cos{\left(2 x - 1 \right)}\, dx \]
    partsIntegrate by parts: u=2*x-1, dv=sin(2*x-1)dx.✓ Proved
  3. \[ = \frac{\left(1 - 2 x\right) \cos{\left(2 x - 1 \right)}}{2} + \frac{\sin{\left(2 x - 1 \right)}}{2} \]
    antiderivative∫cos(2*x-1)dx = sin(2*x-1)/2.✓ Proved
  4. \[ = - \frac{\left(2 x - 1\right) \cos{\left(2 x - 1 \right)}}{2} + \frac{\sin{\left(2 x - 1 \right)}}{2} \]
    simplifyCombine terms over a common denominator.✓ Proved

✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. The full receipt · How we verify

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Problem 4.1340medium Video✓ Nihil obstat
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Problem 4.1353medium VideoReviewed
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Problem 4.1399medium Video✓ Every equation proved
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Problem 4.1400medium Video✓ Every equation proved
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Problem 4.1440medium Video✓ Nihil obstat
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Problem 4.1442medium Video✓ Nihil obstat
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Problem 4.1496medium Video✓ Nihil obstat