Derivatives of compositions: differentiate the outside, keep the inside, multiply by the inside's derivative. 422 problems with worked solutions; in 421 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
rewritealgebraalgebrasimplifyalgebraalgebrasimplifyExpand the trigonometric terms using angle addition formulas. Substitute the value of cos(pi/4) and sin(pi/4). Distribute the values. Combine like terms inside the parentheses. Simplify the coefficient of sin(x). Multiply the negative signs. Simplify the final constant.✓ Proved
Answer \( e^{x} \sin{\left(x \right)} \)
Top: the graph of f = -sqrt(2)·e^(x)·cos(x + pi/4)/2. A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = sqrt(2)·e^(x)·sin(x + pi/4)/2 - sqrt(2)·e^(x)·cos(x + pi/4)/2.
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
algebrasimplifyFactor out exp(x) and combine terms Final simplified derivative✓ 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
Differentiate \( \displaystyle f(x) = x \ln{\left(4 x + 2 \right)} - x + \frac{\ln{\left(2 x + 1 \right)}}{2} \).
\[ \frac{d}{d x} \left(x \ln{\left(4 x + 2 \right)} - x + \frac{\ln{\left(2 x + 1 \right)}}{2}\right) \]
Start with the derivative of the function.✓ Proved
\[ = - \frac{d}{d x} x + \frac{d}{d x} x \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} \]
sumApply the sum rule to separate the terms.✓ Proved
\[ = \frac{d}{d x} x \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} - 1 \]
derivativeDifferentiate the term x.✓ Proved
\[ = x \frac{d}{d x} \ln{\left(4 x + 2 \right)} + \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} - 1 \]
productApply the product rule to the first term.✓ Proved
\[ = \frac{4 x}{4 x + 2} + \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} - 1 \]
chainalgebraApply the chain rule to log(4*x + 2). Multiply the numerator.✓ Proved
\[ = \frac{4 x}{4 x + 2} + \ln{\left(4 x + 2 \right)} + \frac{\frac{d}{d x} \ln{\left(2 x + 1 \right)}}{2} - 1 \]
constant-multiplePull out the constant 1/2.✓ Proved
\[ = \frac{4 x}{4 x + 2} + \ln{\left(4 x + 2 \right)} - 1 + \frac{1}{2 x + 1} \]
chainalgebraApply the chain rule to log(2*x + 1). Simplify the constant multiplication.✓ Proved
\[ = \frac{2 x}{2 x + 1} + \ln{\left(4 x + 2 \right)} - 1 + \frac{1}{2 x + 1} \]
algebraSimplify the fraction (4*x)/(4*x + 2) by dividing by 2.✓ Proved
\[ = \ln{\left(4 x + 2 \right)} \]
algebrasimplifysimplifyCombine the fractions with the same denominator. Simplify the fraction (2*x + 1)/(2*x + 1). Combine the constant terms.✓ Proved
Answer \( \log{\left(4 x + 2 \right)} \)
Top: the graph of f = x·log(4x + 2) - x + log(2x + 1)/2. A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = 4x/(4x + 2) + log(4x + 2) - 1 + 1/(2x + 1).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
\[ \frac{d}{d x} \left(x \ln{\left(4 x + 2 \right)} - x + \frac{\ln{\left(2 x + 1 \right)}}{2}\right) \]
derivative✓ Proved
\[ = - \frac{d}{d x} x + \frac{d}{d x} x \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} \]
sum✓ Proved
\[ = \frac{d}{d x} x \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} - 1 \]
constant✓ Proved
\[ = x \frac{d}{d x} \ln{\left(4 x + 2 \right)} + \ln{\left(4 x + 2 \right)} \frac{d}{d x} x + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} - 1 \]
product✓ Proved
\[ = x \frac{d}{d x} \ln{\left(4 x + 2 \right)} + \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} - 1 \]
constant-multiplesimplify✓ Proved
\[ = \frac{4 x}{4 x + 2} + \ln{\left(4 x + 2 \right)} + \frac{d}{d x} \frac{\ln{\left(2 x + 1 \right)}}{2} - 1 \]
algebrasimplifysimplifyadd fractions cancel 1 final result✓ 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
algebraGroup the terms containing the derivative.✓ Proved
\[ = \frac{\left(x - \frac{3}{4}\right) \frac{d}{d x} \left(4 x - 3\right)}{4 x - 3} + \ln{\left(4 x - 3 \right)} - 1 \]
chainApply the chain rule to the logarithm.✓ Proved
\[ = \ln{\left(4 x - 3 \right)} \]
derivativealgebraalgebrasimplifyThe derivative of 4*x - 3 is 4. Distribute the 4 in the numerator. Simplify the fraction. Final simplification.✓ Proved
Answer \( \log{\left(4 x - 3 \right)} \)
Top: the graph of f = x·log(4x - 3) - x - 3log(4x - 3)/4. A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = 4x/(4x - 3) + log(4x - 3) - 1 - 3/(4x - 3).
A second solution, written separately
By qwen3.6:35b-mlx, without seeing the first. SymPy checked every line.
\[ \frac{d}{d x} \left(x \ln{\left(4 x - 3 \right)} - x - \frac{3 \ln{\left(4 x - 3 \right)}}{4}\right) \]
derivativeStart by expressing the derivative of the given function with respect to x.Not checked
\[ = \frac{d}{d x} \left(- x\right) + \frac{d}{d x} x \ln{\left(4 x - 3 \right)} + \frac{d}{d x} \left(- \frac{3 \ln{\left(4 x - 3 \right)}}{4}\right) \]
sumApply the sum rule to differentiate each term separately.✓ Proved
\[ = \frac{d}{d x} x \ln{\left(4 x - 3 \right)} + \frac{d}{d x} \left(- \frac{3 \ln{\left(4 x - 3 \right)}}{4}\right) - 1 \]
constant-multipleThe derivative of -x is -1, and the constant factor -3/4 can be pulled out of the last term's derivative.✓ Proved
\[ = x \frac{d}{d x} \ln{\left(4 x - 3 \right)} + \ln{\left(4 x - 3 \right)} - \frac{3 \frac{d}{d x} \ln{\left(4 x - 3 \right)}}{4} - 1 \]
productApply the product rule to the first term x*log(4*x - 3).✓ Proved
\[ = \frac{x \frac{d}{d x} \left(4 x - 3\right)}{4 x - 3} + \ln{\left(4 x - 3 \right)} - 1 - \frac{3 \frac{d}{d x} \left(4 x - 3\right)}{4 \left(4 x - 3\right)} \]
chainApply the chain rule to differentiate log(4*x - 3).✓ Proved
\[ = \frac{4 x}{4 x - 3} + \ln{\left(4 x - 3 \right)} - 1 - \frac{3}{4 x - 3} \]
chainsimplifyalgebraDifferentiate the inner function 4*x - 3 to get 4. Simplify the fractions: x*4/(4x-3) becomes 4x/(4x-3) and 3/4 * 4/(4x-3) becomes 3/(4x-3). Remove parentheses for clarity.✓ Proved
\[ = \ln{\left(4 x - 3 \right)} \]
algebrasimplifysimplifyCombine the fractional terms: 4x/(4x-3) - 3/(4x-3) = (4x-3)/(4x-3). Simplify the fraction (4x-3)/(4x-3) to 1. Combine the constants: -1 + 1 = 0.✓ 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
algebraGroup the terms involving the derivative of the logarithm.✓ Proved
\[ = \frac{\left(x + \frac{2}{5}\right) \frac{d}{d x} \left(5 x + 2\right)}{5 x + 2} + \ln{\left(5 x + 2 \right)} - 1 \]
logarithmicApply the chain rule for the derivative of the logarithm.✓ Proved
\[ = \ln{\left(5 x + 2 \right)} \]
derivativealgebrasimplifysimplifyThe derivative of 5*x + 2 is 5. Distribute the 5 into the parentheses. Simplify the fraction. Final simplification.✓ Proved
Answer \( \log{\left(5 x + 2 \right)} \)
Top: the graph of f = x·log(5x + 2) - x + 2log(5x + 2)/5. A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = 5x/(5x + 2) + log(5x + 2) - 1 + 2/(5x + 2).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
\[ \frac{d}{d x} \left(x \ln{\left(5 x + 2 \right)} - x + \frac{2 \ln{\left(5 x + 2 \right)}}{5}\right) \]
derivativerewriteCombine constants✓ Proved
\[ = - \frac{d}{d x} x + \frac{d}{d x} x \ln{\left(5 x + 2 \right)} + \frac{d}{d x} \frac{2 \ln{\left(5 x + 2 \right)}}{5} \]
sumSeparate terms✓ Proved
\[ = x \frac{d}{d x} \ln{\left(5 x + 2 \right)} + \ln{\left(5 x + 2 \right)} \frac{d}{d x} x + \frac{2 \frac{d}{d x} \ln{\left(5 x + 2 \right)}}{5} - 1 \]
productApply product rule to x*log✓ Proved
\[ = \frac{5 x}{5 x + 2} + \ln{\left(5 x + 2 \right)} - 1 + \frac{2}{5 x + 2} \]
algebrasimplifysimplifyCombine fractions Cancel terms Final derivative✓ 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
algebrasimplifyExpand the numerator. Simplify the numerator by canceling terms.✓ Proved
\[ = 5 \ln{\left(x - 3 \right)} \]
algebrasimplifyFactor out the common term 15*log(x - 3) is not correct, let's factor out 5*log(x-3). Cancel the common factor (x - 3).✓ Proved
Answer \( 5 \log{\left(x - 3 \right)} \)
Top: the graph of f = 5x·log(x - 3) - 5x - 15log(x - 3). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = 5x/(x - 3) + 5log(x - 3) - 5 - 15/(x - 3).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
\[ \frac{d}{d x} \left(5 x \ln{\left(x - 3 \right)} - 5 x - 15 \ln{\left(x - 3 \right)}\right) \]
simplifysimplifyCombine fractions Factor 5 from numerator✓ Proved
\[ = 5 \ln{\left(x - 3 \right)} \]
simplifysimplifyCancel (x-3)/(x-3) Final simplified derivative✓ 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
Differentiate \( \displaystyle f(x) = \frac{x}{2} - \frac{\sin{\left(4 x \right)} \cos{\left(4 x \right)}}{8} \).
\[ \frac{d}{d x} \left(\frac{x}{2} - \frac{\sin{\left(4 x \right)} \cos{\left(4 x \right)}}{8}\right) \]
derivativeStart with the derivative of the function.✓ Proved
\[ = \frac{d}{d x} \frac{x}{2} - \frac{d}{d x} \frac{\sin{\left(4 x \right)} \cos{\left(4 x \right)}}{8} \]
sumApply the sum rule.✓ Proved
\[ = \frac{d}{d x} \frac{x}{2} - \frac{\frac{d}{d x} \sin{\left(4 x \right)} \cos{\left(4 x \right)}}{8} \]
constant-multipleFactor out the constant.✓ Proved
\[ = - \frac{\sin{\left(4 x \right)} \frac{d}{d x} \cos{\left(4 x \right)}}{8} - \frac{\cos{\left(4 x \right)} \frac{d}{d x} \sin{\left(4 x \right)}}{8} + \frac{d}{d x} \frac{x}{2} \]
productApply the product rule.✓ Proved
\[ = \frac{\sin^{2}{\left(4 x \right)}}{2} - \frac{\cos^{2}{\left(4 x \right)}}{2} + \frac{d}{d x} \frac{x}{2} \]
chainalgebraApply the chain rule to the trigonometric terms. Simplify the expression inside the parentheses.✓ Proved
\[ = \frac{\sin^{2}{\left(4 x \right)}}{2} - \frac{\cos^{2}{\left(4 x \right)}}{2} + \frac{1}{2} \]
derivativeconstant-multiplealgebraEvaluate the derivative of x/2. Distribute the 1/8. Factor out 1/2.✓ Proved
\[ = \frac{1}{2} - \frac{\cos{\left(8 x \right)}}{2} \]
trigalgebraalgebraUse the double angle identity cos(2*theta) = cos^2(theta) - sin^2(theta). Simplify the argument of the cosine function. Factor out 1/2.✓ Proved
\[ = \sin^{2}{\left(4 x \right)} \]
simplifyUse the identity 1 - cos(2*theta) = 2*sin(theta)**2 with theta = 4*x.✓ Proved
Answer \( \sin^{2}{\left(4 x \right)} \)
Top: the graph of f = x/2 - sin(4x)·cos(4x)/8. A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = sin(4x)²/2 - cos(4x)²/2 + 1/2.
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
\[ \frac{d}{d x} \left(\frac{x}{2} - \frac{\sin{\left(4 x \right)} \cos{\left(4 x \right)}}{8}\right) \]
derivative✓ Proved
\[ = \frac{d}{d x} \frac{x}{2} - \frac{d}{d x} \frac{\sin{\left(4 x \right)} \cos{\left(4 x \right)}}{8} \]
sumSeparate the derivative of each term.✓ Proved
\[ = \frac{d}{d x} \frac{x}{2} - \frac{\frac{d}{d x} \sin{\left(4 x \right)} \cos{\left(4 x \right)}}{8} \]
constant-multiplePull out the constant 1/8.✓ Proved
\[ = - \frac{\sin{\left(4 x \right)} \frac{d}{d x} \cos{\left(4 x \right)}}{8} - \frac{\cos{\left(4 x \right)} \frac{d}{d x} \sin{\left(4 x \right)}}{8} + \frac{d}{d x} \frac{x}{2} \]
productApply product rule to sin(4*x)*cos(4*x).✓ 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
Differentiate \( \displaystyle f(x) = \operatorname{atan}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)} \right)} \).
\[ \frac{d}{d x} \operatorname{atan}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)} \right)} \]
derivativeStart with the derivative of the function.✓ Proved
\[ = \frac{\frac{d}{d x} \left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
chainApply the chain rule for the arctangent function.✓ Proved
\[ = \frac{\frac{d}{d x} \cot{\left(3 x \right)} + \frac{d}{d x} \csc{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
sumApply the sum rule to the inner derivative.✓ Proved
\[ = \frac{- 3 \csc^{2}{\left(3 x \right)} + \frac{d}{d x} \csc{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
derivativeDifferentiate the cotangent term.✓ Proved
\[ = \frac{- 3 \cot{\left(3 x \right)} \csc{\left(3 x \right)} - 3 \csc^{2}{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
derivativeDifferentiate the cosecant term.✓ Proved
\[ = - \frac{3 \left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right) \csc{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
algebraalgebraFactor out common terms in the numerator. Combine the expression into a single fraction.✓ Proved
\[ = - \frac{3 \left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right) \csc{\left(3 x \right)}}{\cot^{2}{\left(3 x \right)} + 2 \cot{\left(3 x \right)} \csc{\left(3 x \right)} + \csc^{2}{\left(3 x \right)} + 1} \]
algebraExpand the squared term in the denominator.✓ Proved
\[ = - \frac{3 \left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right) \csc{\left(3 x \right)}}{2 \cot{\left(3 x \right)} \csc{\left(3 x \right)} + 2 \csc^{2}{\left(3 x \right)}} \]
algebrasimplifyUse the identity cot(3*x)**2 = csc(3*x)**2 - 1. Simplify the denominator by combining like terms.✓ Proved
\[ = - \frac{3}{2} \]
algebrasimplifysimplifyFactor the denominator. Cancel the common factor (csc(3*x) + cot(3*x)). Cancel the common factor csc(3*x) to get the final result.✓ Proved
Answer \( - \frac{3}{2} \)
Top: the graph of f = atan(cot(3x) + csc(3x)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = (-3cot(3x)² - 3cot(3x)·csc(3x) - 3)/((cot(3x) + csc(3x))² + 1).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
\[ \frac{d}{d x} \operatorname{atan}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)} \right)} \]
derivative✓ Proved
\[ = \frac{\frac{d}{d x} \left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
chain✓ Proved
\[ = \frac{\frac{d}{d x} \cot{\left(3 x \right)} + \frac{d}{d x} \csc{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
sum✓ Proved
\[ = \frac{- 3 \csc^{2}{\left(3 x \right)} + \frac{d}{d x} \csc{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
derivative✓ Proved
\[ = \frac{- 3 \cot{\left(3 x \right)} \csc{\left(3 x \right)} - 3 \csc^{2}{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
derivativealgebra✓ Proved
\[ = - \frac{3 \left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right) \csc{\left(3 x \right)}}{\left(\cot{\left(3 x \right)} + \csc{\left(3 x \right)}\right)^{2} + 1} \]
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
algebraalgebraCombine the fractions with the same denominator. Factor the numerator of the fraction.✓ Proved
\[ = 2 \ln{\left(x + 2 \right)} \]
simplifysimplifyCancel the common factor (x + 2). Simplify the remaining constant terms.✓ Proved
Answer \( 2 \log{\left(x + 2 \right)} \)
Top: the graph of f = 2x·log(x + 2) - 2x + 4log(x + 2). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = 2x/(x + 2) + 2log(x + 2) - 2 + 4/(x + 2).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
\[ \frac{d}{d x} \left(2 x \ln{\left(x + 2 \right)} - 2 x + 4 \ln{\left(x + 2 \right)}\right) \]
✓ 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
productsimplifyDifferentiate the product x*(1 - x**2)**(-1/2) Simplify the derivative of the second factor✓ Proved
\[ = \frac{1}{x \left(1 - x^{2}\right)} \]
simplifysimplifysimplifyCombine terms in the numerator Subtract exponents and simplify Final simplified derivative✓ 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
trigalgebraDifferentiate the cosine function. Simplify the signs and the fraction.✓ Proved
\[ = \tan{\left(x + 1 \right)} + 1 \]
trigUse the identity tan(u) = sin(u)/cos(u).✓ Proved
Answer \( \tan{\left(x + 1 \right)} + 1 \)
Top: the graph of f = log(e^(x + 1)/cos(x + 1)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = (e^(x + 1)·sin(x + 1)/cos(x + 1)² + e^(x + 1)/cos(x + 1))·e^(-x - 1)·cos(x + 1).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
✓ 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
constantThe derivative of the constant log(4) is 0.✓ Proved
\[ = 2 - \frac{d}{d x} 2 \ln{\left(x \right)} \]
rewriteUse the power rule for logarithms: log(x**2) = 2*log(x).✓ Proved
\[ = 2 - 2 \frac{d}{d x} \ln{\left(x \right)} \]
constant-multiplePull the constant factor 2 out of the derivative.✓ Proved
\[ = 2 - \frac{2}{x} \]
derivativesimplifyThe derivative of log(x) is 1/x. Simplify the expression.✓ Proved
Answer \( 2 - \frac{2}{x} \)
Top: the graph of f = log(e^(2x)/(4x²)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = 4x²·(e^(2x)/(2x²) - e^(2x)/(2x³))·e^(-2x).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
✓ 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
chainApply the chain rule to the second term.✓ Proved
\[ = - \frac{x}{x^{2} + 1} + \frac{1}{x} \]
derivativealgebraDifferentiate the inner function x**2 + 1. Simplify the expression by canceling the 2 and the 1/2.✓ Proved
\[ = \frac{1}{x \left(x^{2} + 1\right)} \]
algebrasimplifyFind a common denominator to combine the terms. Simplify the numerator.✓ Proved
Answer \( \frac{1}{x^{3} + x} \)
Top: the graph of f = log(x/sqrt(x² + 1)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = sqrt(x² + 1)·(-x²/(x² + 1)^(3/2) + 1/sqrt(x² + 1))/x.
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
productDifferentiate x*(x**2+1)**(-1/2) using product rule✓ Proved
\[ = \frac{1}{x \left(x^{2} + 1\right)} \]
simplifysimplifysimplifyFactor common power Combine powers and cancel Final simplified derivative✓ 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
logarithmicconstant-multipleThe derivative of log(x - 3) is 1/(x - 3). Simplify the coefficients.✓ Proved
\[ = \ln{\left(x - 3 \right)} \]
algebrasimplifysimplifyCombine the fractions with the same denominator. Simplify the fraction (x-3)/(x-3). Final simplification.✓ Proved
Answer \( \log{\left(x - 3 \right)} \)
Top: the graph of f = x·log(x - 3) - x - 3log(x - 3). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = x/(x - 3) + log(x - 3) - 1 - 3/(x - 3).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
✓ 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
algebraDistribute the negative sign and the fraction.✓ Proved
\[ = \csc{\left(x - 1 \right)} \]
algebrasimplifyFactor out csc(x - 1) from the numerator. Cancel the common term in the numerator and denominator.✓ Proved
Answer \( \frac{1}{\sin{\left(x - 1 \right)}} \)
Top: the graph of f = -log(cot(x - 1) + csc(x - 1)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = -(-cot(x - 1)² - cot(x - 1)·csc(x - 1) - 1)/(cot(x - 1) + csc(x - 1)).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
algebrasimplifyfactor numerator cancel common factor✓ 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
algebraDistribute the negative sign and the constant.✓ Proved
\[ = 3 \csc{\left(x - 3 \right)} \]
algebrasimplifyFactor out csc(x - 3) from the numerator. Cancel the common term in the numerator and denominator.✓ Proved
Answer \( \frac{3}{\sin{\left(x - 3 \right)}} \)
Top: the graph of f = -3log(cot(x - 3) + csc(x - 3)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = -3(-cot(x - 3)² - cot(x - 3)·csc(x - 3) - 1)/(cot(x - 3) + csc(x - 3)).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
simplifyThe numerator and denominator cancel, leaving 3*csc(x-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
trigalgebraThe derivative of cos(x - 1) is -sin(x - 1). Simplify the fraction.✓ Proved
\[ = \tan{\left(x - 1 \right)} - 1 \]
trigalgebraUse the identity tan(u) = sin(u)/cos(u). Rearrange the terms.✓ Proved
Answer \( \tan{\left(x - 1 \right)} - 1 \)
Top: the graph of f = log(e^(1 - x)/cos(x - 1)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = (e^(1 - x)·sin(x - 1)/cos(x - 1)² - e^(1 - x)/cos(x - 1))·e^(x - 1)·cos(x - 1).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
✓ 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
derivativeEvaluate the derivatives of the inner linear terms.✓ Proved
\[ = \csc{\left(x + 2 \right)} \]
algebraalgebrasimplifyFactor out the common term -csc(x + 2). Cancel the common term in the numerator and denominator. Simplify the remaining expression.✓ Proved
Answer \( \frac{1}{\sin{\left(x + 2 \right)}} \)
Top: the graph of f = -log(cot(x + 2) + csc(x + 2)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = -(-cot(x + 2)² - cot(x + 2)·csc(x + 2) - 1)/(cot(x + 2) + csc(x + 2)).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
derivativesimplifyDerivative of cot(u) is -csc(u)**2, derivative of csc(u) is -csc(u)*cot(u). Remove the double negative.✓ Proved
\[ = \csc{\left(x + 2 \right)} \]
simplifyFactor csc(x+2) and cancel with the 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
chainDerivative of sin(2*x) is cos(2*x) times derivative of 2*x.✓ Proved
\[ = \frac{5}{2} - \frac{5 \cos{\left(2 x \right)}}{2} \]
derivativesimplifyDerivative of 2*x is 2. Multiply 5/4 by 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
derivativealgebraEvaluate the derivatives of the inner linear terms. Simplify the expression inside the parentheses.✓ Proved
\[ = \csc{\left(x + 1 \right)} \]
algebrasimplifyFactor out csc(x + 1) from the numerator and rearrange the denominator. Cancel the common term in the numerator and denominator.✓ Proved
Answer \( \frac{1}{\sin{\left(x + 1 \right)}} \)
Top: the graph of f = log(-cot(x + 1) + csc(x + 1)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = (cot(x + 1)² - cot(x + 1)·csc(x + 1) + 1)/(-cot(x + 1) + csc(x + 1)).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
✓ 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
trigalgebraThe derivative of cos(x - 1) is -sin(x - 1). Simplify the fraction.✓ Proved
\[ = \tan{\left(x - 1 \right)} + 1 \]
trigUse the identity sin(u)/cos(u) = tan(u).✓ Proved
Answer \( \tan{\left(x - 1 \right)} + 1 \)
Top: the graph of f = log(e^(x - 1)/cos(x - 1)). A tangent line slides along it, and its slope is plotted below as it goes, tracing f' = (e^(x - 1)·sin(x - 1)/cos(x - 1)² + e^(x - 1)/cos(x - 1))·e^(1 - x)·cos(x - 1).
A second solution, written separately
By gpt-oss:20b, without seeing the first. SymPy checked every line.
✓ 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