Math 181-Winter 2022 Exam 1
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Math 181-Winter 2022
Exam 1(Chapter 6)
1. Sketch the region A enclosed by the given curves and find its area. (10pts)
y = -2 + 4, y=2x+1
a) Graph the bounded region. (2pts)
b) Area of a typical rectangle in each interval. (4pts) c) Set up the Area integration. Then find A.(4pts)
2. R={ = 1 − 2 and y = 0}. Sketch the region R and find the volume of the solid generated when it’s revolved about the y=3. Use washer method.
a) Graph the region R.(2pts)
b) (2pts)Rout= Rin=
c) Area of a cross section.(3pts)
d) Write the volume integral and find the volume. (3pts)
3. V={y = sin x, y = cos x, x = 0, and x = π/4}
Sketch region V and find the volume of the solid generated when it’s revolved around the y-axis . Use Disk
Method.
Graph the bounded region: (3pts)
b) Area of a cross section.(3pts)
c) Write the volume integral and find the volume.(4pts)
4. Use cylindrical shells to find the volume of the solid obtained by rotating about the x-axis the region bounded by the given curves. (10pts)
2 − 3 + = 0, = 0
a) Graph bounded region: (2pts)
b) circumference of a typical shell (1pt)=
c) height a typical shell (1pt)=
d) thickness a typical shell (1pt)=
e) Write volume integral and find the volume. (5pts)
5. Find the volume of the solid whose base is bounded by
= x2, = 4 with equilateral triangle cross sections parallel to the x-axis.
a) Graph the bounded region:(3pts)
b) Area of a cross section. (3pts)
c) Write the volume integral and find the volume.(4pts)
6. A work of 30 ft- lb is required to stretch a spring from its natural length of 10 in to a length of 18 in. Find the work done in stretching the spring from its natural length to a length of 50 in. (5pts each)
a) Find K, string constant.
b) Find the work done in stretching the spring from its natural length to a length of 50 in.
7. a) Find the average value of the function on the interval [1, 3]. (5pts)
b) Find c such that = (). (5pts)
8. A circular swimming pool has a radius of 18 ft, the sides are 9 ft high, and the depth ofthe water is 5 ft. How much work is required to pump all of the water out over the side? (5pts)
( Use the fact that water weighs 62.5 lb/ft3.)
2022-01-20