## Educators

Rk
ss
RG
+ 3 more educators

### Problem 1

Find the area of the shaded region.

Check back soon!

### Problem 2

Find the area of the shaded region.

SL
Sky L.

### Problem 3

Find the area of the shaded region.

SL
Sky L.

### Problem 4

Find the area of the shaded region.

SL
Sky L.

### Problem 5

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$y = e^x$ , $y = x^2 - 1$ , $x = -1$ , $x = 1$

SL
Sky L.

### Problem 6

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$y = \sin x$ , $y = x$ , $x = \frac{\pi}{2}$ , $x = \pi$

SL
Sky L.

### Problem 7

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$y = (x - 2)^2$ , $y = x$

SL
Sky L.

### Problem 8

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$y = x^2 - 4x$ , $y = 2x$

SL
Sky L.

### Problem 9

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$y = \frac{1}{x}$ , $y = \frac{1}{x^2}$ , $x = 2$

SL
Sky L.

### Problem 10

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$y = \sin x$ , $y = \frac{2x}{\pi}$ , $x \ge 0$

SL
Sky L.

### Problem 11

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$x = 1 - y^2$ , $x = y^2 - 1$

SL
Sky L.

### Problem 12

Sketch the region enclosed by the given curves. Decide whether to integrate with respect to $x$ and $y$. Draw a typical approximating rectangle and label its height and width. Then find the area of the region.

$4x + y^2 = 12$ , $x = y$

SL
Sky L.

### Problem 13

Sketch the region enclosed by the given curves and find its area.

$y = 12 - x^2$ , $y = x^2 - 6$

SL
Sky L.

### Problem 14

Sketch the region enclosed by the given curves and find its area.

$y = x^2$ , $y = 4x - x^2$

SL
Sky L.

### Problem 15

Sketch the region enclosed by the given curves and find its area.

$y = \sec^2 x$ , $y = 8 \cos x$ , $\frac{-\pi}{3} \le x \le \frac{\pi}{3}$

SL
Sky L.

### Problem 16

Sketch the region enclosed by the given curves and find its area.

$y = \cos x$ , $y = 2 - \cos x$ , $0 \le x \le 2\pi$

SL
Sky L.

### Problem 17

Sketch the region enclosed by the given curves and find its area.

$x = 2y^2$ , $x = 4 + y^2$

SL
Sky L.

### Problem 18

Sketch the region enclosed by the given curves and find its area.

$y = \sqrt{x - 1}$ , $x - y = 1$

SL
Sky L.

### Problem 19

Sketch the region enclosed by the given curves and find its area.

$y = \cos \pi x$ , $y = 4x^2 - 1$

SL
Sky L.

### Problem 20

Sketch the region enclosed by the given curves and find its area.

$x = y^4$ , $y = \sqrt{2 - 1}$ , $y = 0$

SL
Sky L.

### Problem 21

Sketch the region enclosed by the given curves and find its area.

$y = \tan x$ , $y = 2 \sin x$ , $\frac{-\pi}{3} \le x \le \frac{\pi}{3}$

SL
Sky L.

### Problem 22

Sketch the region enclosed by the given curves and find its area.

$y = x ^3$ , $y = x$

SL
Sky L.

### Problem 23

Sketch the region enclosed by the given curves and find its area.

$y = \sqrt[3]{2x}$ , $y = \frac{1}{8}x^2$ , $0 \le x \le 6$

SL
Sky L.

### Problem 24

Sketch the region enclosed by the given curves and find its area.

$y = \cos x$ , $y = 1 - \cos x$ , $0 \le x \le \pi$

AS
Apoorva S.

### Problem 25

Sketch the region enclosed by the given curves and find its area.

$y = x^4$ , $y = 2 - \mid x \mid$

Catherine R.

### Problem 26

Sketch the region enclosed by the given curves and find its area.

$y = \sinh x$ , $y = e^{-x}$ , $x = 0$ , $x = 2$

Kenneth K.

### Problem 27

Sketch the region enclosed by the given curves and find its area.

$y = \frac{1}{x}$ , $y = x$ , $y = \frac{1}{4}x$ , $x > 0$

Kenneth K.

### Problem 28

Sketch the region enclosed by the given curves and find its area.

$y = \frac{1}{4}x^2$ , $y = 2x^2$ , $x + y = 3$ , $x \ge 0$

Kenneth K.

### Problem 29

The graphs of two functions are shown with the areas of the regions between the curves indicated.
(a) What is the total area between the curves for $0 \le x \le 5$?
(b) What is the value of $\displaystyle \int_{0}^5 [f(x) - g(x)] dx$?

Kenneth K.

### Problem 30

Sketch the region enclosed by the given curves and find its area.

$y = \frac{x}{\sqrt{1 + x^2}}$ , $y = \frac{x}{\sqrt{9 - x^2}}$ , $x \ge 0$

Kenneth K.

### Problem 31

Sketch the region enclosed by the given curves and find its area.

$y = \frac{x}{1 + x^2}$ , $y = \frac{x^2}{1 + x^3}$

Kenneth K.

### Problem 32

Sketch the region enclosed by the given curves and find its area.

$y = \frac{\ln x}{x}$ , $y = \frac{(\ln x)^2}{x}$

Kenneth K.

### Problem 33

Use calculus to find the area of the triangle with the given vertices.

$(0 , 0)$ , $(3 , 1)$ , $(1 , 2)$

Kenneth K.

### Problem 34

Use calculus to find the area of the triangle with the given vertices.

$(2 , 0)$ , $(0 , 2)$ , $(-1 , 1)$

Kenneth K.

### Problem 35

Evaluate the integral and interpret it as the area of a region. Sketch the region.

$\displaystyle \int_{0}^{\frac{\pi}{2}} \mid \sin x - \cos 2x \mid dx$

Kenneth K.

### Problem 36

Evaluate the integral and interpret it as the area of a region. Sketch the region.

$\displaystyle \int_{-1}^1 \mid 3^x - 2^x \mid dx$

Kenneth K.

### Problem 37

Use a graph to find approximate x-coordinates of the points of intersection of the given curves. Then find (approximately) the area of the region bounded by the curves.

$y = x \sin (x^2)$ , $y = x^4$ , $x \ge 0$

Kenneth K.

### Problem 38

Use a graph to find approximate x-coordinates of the points of intersection of the given curves. Then find (approximately) the area of the region bounded by the curves.

$y = \frac{x}{(x^2 + 1)^2}$ , $y = x^5 - x$ , $x \ge 0$

Kenneth K.

### Problem 39

Use a graph to find approximate x-coordinates of the points of intersection of the given curves. Then find (approximately) the area of the region bounded by the curves.

$y = 3x^2 - 2x$ , $y = x^3 - 3x + 4$

Kenneth K.

### Problem 40

Use a graph to find approximate x-coordinates of the points of intersection of the given curves. Then find (approximately) the area of the region bounded by the curves.

$y = 1.3^x$ , $y = 2 \sqrt{x}$

Kenneth K.

### Problem 41

Graph the region between the curves and use your calculator to compute the area correct to five decimal places.

$y = \frac{2}{1 + x^4}$ , $y = x^2$

Kenneth K.

### Problem 42

Graph the region between the curves and use your calculator to compute the area correct to five decimal places.

$y = e^{1 - x^2}$ , $y = x^4$

Kenneth K.

### Problem 43

Graph the region between the curves and use your calculator to compute the area correct to five decimal places.

$y = \tan^2 x$ , $y = \sqrt{x}$

Kenneth K.

### Problem 44

Graph the region between the curves and use your calculator to compute the area correct to five decimal places.

$y = \cos x$ , $y = x + 2 \sin^4 x$

Kenneth K.

### Problem 45

Use a computer algebra system to find the exact area enclosed by the curves $y = x^5 - 6x^3 + 4x$ and $y = x$.

Kenneth K.

### Problem 46

Sketch the region in the xy-plane defined by the inequalities $x - 2y^2 \ge 0$ , $1 - x - \mid y \mid \ge 0$ and find its area.

Kenneth K.

### Problem 47

Racing cars driven by Chris and Kelly are side by side at the start of a race. The table shows the velocities of each car (in miles per hour) during the first ten seconds of the race. Use the Midpoint Rule to estimate how much farther Kelly travels than Chris does during the first ten seconds.

Kenneth K.

### Problem 48

The widths (in meters) of a kidney-shaped swimming pool were measured at 2-meter intervals as indicated in the figure. Use the Midpoint Rule to estimate the area of the pool.

Kenneth K.

### Problem 49

A cross-section of an airplane wing is shown. Measurements of the thickness of the wing, in centimeters, at 20-centimeter intervals are 5.8, 20.3, 26.7, 29.0, 27.6, 27.3, 23.8, 20.5, 15.1, 8.7, and 2.8. Use the Midpoint Rule to estimate the area of the wing's cross section.

Kenneth K.

### Problem 50

If the birth rate of a population is $b(t) = 2200 e^{0.024t}$ people per year and the death rate is $d(t) = 1460 e^{0.018t}$ people per year, find the area between these curves for $0 \le t \le 10$. What does this area represent?

Bowen G.

### Problem 51

In Example 5, we modeled a measles pathogenesis curve by a function $f$. A patient infected with the measles virus who has some immunity to the virus has a pathogenesis curve that can be modeled by, for instance, $g(t) = 0.9 f(t)$.
(a) If the same threshold concentration of the virus is required for infectiousness to begin as in Example 5, on what day does this occur?
(b) Let $P_3$ be the point of the graph of $g$ where infectiousness begin. It has been shown that infectiousness ends at a point $P_4$ on the graph of $g$ where the line through $P_3$, $P_4$ has the same slope as the line through $P_1$, $P_2$ in Example 5(b). On what day does infectiousness end?
(c) Compute the level of infectiousness for this patient.

CC
Charles C.

### Problem 52

The rates at which rain fell, in inches per hour, in two different locations $t$ hours after the start of a storm are given by $f(t) = 0.73t^3 - 2t^2 + t + 0.6$ and $g(t) = 0.17t^2 - 0.5t + 1.1$. Compute the area between the graphs for $0 \le t \le 2$ and interpret your result in this context.

Catherine R.

### Problem 53

Two cars, A and B, start side by side and accelerate from rest. The figure shows the graphs of their velocity functions.
(a) Which car is ahead after one minute? Explain.
(b) What is the meaning of the area of the shaded region?
(c) Which car is ahead after two minutes? Explain.
(d) Estimate the time at which the cars are again side by side.

CC
Charles C.

### Problem 54

The figure shows graphs of the marginal revenue function $R'$ and the marginal cost function $C'$ for a manufacturer. [Recall from Section 4.7 that $R(x)$ and $C(x)$ represent the revenue and cost when $x$ units are manufactured. Assume that $R$ and $C$ are measured in thousands of dollars.] What is the meaning of the area of the shaded region? Use the Midpoint Rule to estimate the value of this quantity.

### Problem 55

The curve with equation $y^2 = x^2 (x + 3)$ is called Tschirnhausen's cubic. If you graph this curve you will see that part of the curve forms a loop. Find the area enclosed by the loop.

### Problem 56

Find the area of the region bounded by the parabola $y = x^2$, the tangent line to this parabola at $(1, 1)$, and the x-axis.

Catherine R.

### Problem 57

Find the number $b$ such that the line $y = b$ divides the region bounded by the curves $y = x^2$ and $y = 4$ into two regions with equal area.

Catherine R.

### Problem 58

(a) Find the number a such that the line $x = a$ bisects the area under the curve $y = \frac{1}{x^2}$, $1 \le x \le 4$.

Catherine R.

### Problem 59

Find the values of $c$ such that the area of the region bounded by the parabolas $y = x^2 - c^2$ and $y = c^2 - x^2$ is 576.

Catherine R.
Suppose that $0 < c < \frac{\pi}{2}$. For what value of $c$ is the area of the region enclosed by the curves $y = \cos x$, $y = \cos (x - c)$, and $x = 0$ equal to the area of the region enclosed by the curves $y = \cos (x - c)$, $x = \pi$, and $y = 0$.
For what values of $m$ do the line $y = mx$ and the curve $y = \frac{x}{(x^2 + 1)}$ enclose a region? Find the area of the region.