Double integrals over general regions practice problems
Type I and Type II regions: set the bounds, then integrate. 48 problems with worked solutions; in 48 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. How we verify
Evaluate \( \displaystyle \iint_D x^{2} \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = \sqrt{x} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to sqrt(x).
Reviewed
\[ \int\limits_{0}^{\sqrt{x}} x^{2}\, dy = x^{\frac{5}{2}} \]
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x + y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = \sqrt{x} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to sqrt(x).
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 2 x \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = \sqrt{x} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to sqrt(x).
Reviewed
\[ \int\limits_{0}^{\sqrt{x}} 2 x\, dy = 2 x^{\frac{3}{2}} \]
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x^{2} \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to x.
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x + y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to x.
Reviewed
\[ \int\limits_{0}^{x} \left(x + y\right)\, dy = \frac{3 x^{2}}{2} \]
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 2 x \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = 2 x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to 2*x.
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to x.
Reviewed
\[ \int\limits_{0}^{x} x y\, dy = \frac{x^{3}}{2} \]
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 2 x \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x^{2} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to x**2.
Reviewed
\[ \int\limits_{0}^{x^{2}} 2 x\, dy = 2 x^{3} \]
The inner integral.✓ Proved
\[ \int\limits_{0}^{2} 2 x^{3}\, dx = 8 \]
The outer integral.✓ Proved
Answer \( 8 \)
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 6 x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x^{2} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to x**2.
Reviewed
\[ \int\limits_{0}^{x^{2}} 6 x y\, dy = 3 x^{5} \]
The inner integral.✓ Proved
\[ \int\limits_{0}^{2} 3 x^{5}\, dx = 32 \]
The outer integral.✓ Proved
Answer \( 32 \)
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = 2 x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to 2*x.
Reviewed
\[ \int\limits_{0}^{2 x} x y\, dy = 2 x^{3} \]
The inner integral.✓ Proved
\[ \int\limits_{0}^{2} 2 x^{3}\, dx = 8 \]
The outer integral.✓ Proved
Answer \( 8 \)
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = \sqrt{x} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to sqrt(x).
Reviewed
\[ \int\limits_{0}^{\sqrt{x}} x y\, dy = \frac{x^{2}}{2} \]
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 6 x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to x.
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 2 x \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to x.
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x^{2} \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = 2 x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to 2*x.
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to x.
Reviewed
\[ \int\limits_{0}^{x} y\, dy = \frac{x^{2}}{2} \]
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 6 x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = 2 x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to 2*x.
Reviewed
\[ \int\limits_{0}^{2 x} 6 x y\, dy = 12 x^{3} \]
The inner integral.✓ Proved
\[ \int\limits_{0}^{2} 12 x^{3}\, dx = 48 \]
The outer integral.✓ Proved
Answer \( 48 \)
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D 6 x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = \sqrt{x} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to sqrt(x).
Reviewed
\[ \int\limits_{0}^{\sqrt{x}} 6 x y\, dy = 3 x^{2} \]
The inner integral.✓ Proved
\[ \int\limits_{0}^{1} 3 x^{2}\, dx = 1 \]
The outer integral.✓ Proved
Answer \( 1 \)
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D x y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = x^{2} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 1 \).
D is Type I: for each x in [0, 1], y runs from 0 to x**2.
Reviewed
\[ \int\limits_{0}^{x^{2}} x y\, dy = \frac{x^{5}}{2} \]
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = \sqrt{x} \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to sqrt(x).
Reviewed
\[ \int\limits_{0}^{\sqrt{x}} y\, dy = \frac{x}{2} \]
The inner integral.✓ Proved
\[ \int\limits_{0}^{2} \frac{x}{2}\, dx = 1 \]
The outer integral.✓ Proved
Answer \( 1 \)
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
Evaluate \( \displaystyle \iint_D y \, dA \) where D is bounded by \( \displaystyle y = 0 \), \( \displaystyle y = 2 x \), \( \displaystyle x = 0 \) and \( \displaystyle x = 2 \).
D is Type I: for each x in [0, 2], y runs from 0 to 2*x.
✓ Nihil obstat Lines: 2 proved, 1 reviewed. 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
More double integrals over general regions practice