Let the region R be the area enclosed by the function f(x)=x+2, the horizontal line y=−1 and the vertical lines x=0 and x=6. Find the volume of the solid generated when the region R is revolved about the line y=6. You may use a calculator and round to the nearest thousandth.
Q. Let the region R be the area enclosed by the function f(x)=x+2, the horizontal line y=−1 and the vertical lines x=0 and x=6. Find the volume of the solid generated when the region R is revolved about the line y=6. You may use a calculator and round to the nearest thousandth.
Set up integral: First, we need to set up the integral for the volume using the disk method since we're revolving around a horizontal line.
Adjust functions: The volume V of a solid of revolution generated by revolving a region bounded by y=f(x), y=g(x), x=a, and x=b around the x-axis is given by the integral from a to b of π(f(x)2−g(x)2)dx. Here, we're revolving around y=6, so we need to adjust the functions to account for this.
Calculate limits: The adjusted functions will be (6−(x+2))2 for the top function and (6−(−1))2 for the bottom function. The limits of integration are from x=0 to x=6.
Simplify integral: Set up the integral: V=π∫06[(6−(x+2))2−(6−(−1))2]dx.
Calculate integral: Simplify the integral: V=π∫06[(4−x)2−49]dx.
Further simplify: Now we calculate the integral using a calculator: V≈π∫06[(16−8x+x)−49]dx.
Integrate terms: Further simplify the integral: V≈π∫06[−33−8x+x]dx.
Plug in limits: Integrate term by term: V≈π[−33x−316x23+21x2] from 0 to 6.
Calculate values: Plug in the limits of integration: V \approx \pi[\(-33(6) - (16/3)(6)^{3/2} + (1/2)(6)^2] - \pi[−33(0) - (16/3)(0)^{3/2} + (1/2)(0)^2].
Simplify square root: Calculate the values: V≈π[−198−(316)(216)21+18].
Finish calculation: Simplify the square root and continue the calculation: V≈π[−198−(316)⋅14.7+18].
Add numbers: Finish the calculation: V≈π[−198−78.4+18].
Add numbers: Finish the calculation: V≈π[−198−78.4+18].Add up the numbers: V≈π[−258.4].
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