Integrate top minus bottom between the points where the curves cross. 70 problems with worked solutions; in 70 of them every
equation is proved by a computer algebra system.
12 worked problems
Try each one before opening the solution. Every line is labeled with what checked it. How we verify
The curves y = -x² + 4x + 3 and y = 3x + 1 between x = -1 and x = 2. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 9/2.
✓ 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
The curves y = -3x² + 14x - 11 and y = 2x - 2 between x = 1 and x = 3. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 4.
✓ 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
The curves y = -x² - x + 10 and y = 2 - 3x between x = -2 and x = 4. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 36.
✓ 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
The curves y = -x² - 1 and y = 2x - 1 between x = -2 and x = 0. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 4/3.
✓ 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
The curves y = -2x² + 6x - 3 and y = -2x - 3 between x = 0 and x = 4. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 64/3.
✓ 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
The curves y = -x² - 5x - 1 and y = -2x - 1 between x = -3 and x = 0. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 9/2.
✓ 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
The curves y = -2x² + 9x + 7 and y = 3x - 1 between x = -1 and x = 4. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 125/3.
✓ 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
The curves y = 3 - 2x² and y = 2x - 1 between x = -2 and x = 1. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 9.
✓ 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
The curves y = -x² + 2x + 10 and y = x - 2 between x = -3 and x = 4. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 343/6.
✓ 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
The curves y = 15 - 3x² and y = -3x - 3 between x = -2 and x = 3. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 125/2.
✓ 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
The curves y = -2x² + 3x - 1 and y = x - 1 between x = 0 and x = 1. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 1/3.
✓ 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
The curves y = -2x² + 11x + 3 and y = 3x + 3 between x = 0 and x = 4. Thin rectangles fill the gap between them, getting narrower until they fill the region exactly; its area is 64/3.
✓ 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