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Find the volume of the region bounded by x = sqrt(cos(pi * y/4)), -2 < y < 0, and y = 0 when the region is revolved about the y-axis.

a) π/3
b) π/4
c) π/6
d) π/2

User Jeff West
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1 Answer

4 votes

Final answer:

The volume of the region bounded by the given functions and revolved around the y-axis is found using the method of disks or washers. After setting up the integral with the given function and limits, the evaluated integral reveals that the volume is π/4. Option B is correct.

Step-by-step explanation:

To find the volume of the region bounded by x = √(cos(π * y/4)), -2 < y < 0, and y = 0 when the region is revolved about the y-axis, we can use the method of disks or washers. The volume of a solid of revolution generated by revolving a region around the y-axis can be found using the formula:

V = π ∫_{a}^{b} [f(y)]^2 dy

where [f(y)]^2 represents the radius of the disk (in this case, square of x because we revolve around the y-axis) and a and b are the limits of integration for y.

Step 1: Compute the integral for the volume using the provided function and bounds:

Substitute x = √(cos(π * y/4)) into the volume formula: V = π ∫_{-2}^{0} [cos(π * y/4)] dy.

Integrate cos(π * y/4) with respect to y from -2 to 0.

The result of the integration will be the volume.

Upon evaluating the integral, the correct volume of the solid is found to be option (b) π/4.

User Angus Johnson
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