Q. Revolve the region bounded by y=ex, the x-axis, x=0, and x=1 about the line y=4. Find the volume.V=[?]
Set up integral for volume: First, we need to set up the integral for the volume using the disk method since we're revolving around a horizontal line. The volume of a solid of revolution is given by the integral of π(outer radius2−inner radius2) from a to b.
Determine outer and inner radius: The outer radius is the distance from y=4 to y=ex, which is 4−ex. The inner radius is 0 because the region is bounded by the x-axis (y=0). So, we only need to consider the outer radius.
Calculate volume integral: Now we set up the integral: V=π∫01(4−ex)2dx. This will give us the volume of the solid.
Expand and simplify expression: We need to expand (4−ex)2 to (16−8ex+e2x) before integrating.
Integrate term by term: Now we integrate: V=π⋅[∫0116dx−∫018exdx+∫01e2xdx].
Evaluate limits of integration: Integrating term by term, we get V=π⋅[16x−8ex+(21)e2x] evaluated from 0 to 1.
Simplify the expression: Plugging in the limits of integration, we get V=π⋅[(16⋅1−8e1+(1/2)e2⋅1)−(16⋅0−8e0+(1/2)e2⋅0)].
Combine like terms: Simplify the expression: V=π⋅[16−8e+(21)e2−(0−8⋅1+(21)⋅1)].
Calculate numerical value: Further simplification gives us V=π⋅[16−8e+(21)e2−8+(21)].
Calculate numerical value: Further simplification gives us V=π×[16−8e+(21)e2−8+(21)].Combine like terms: V=π×[8−8e+(21)e2+(21)].
Calculate numerical value: Further simplification gives us V=π×[16−8e+(1/2)e2−8+(1/2)].Combine like terms: V=π×[8−8e+(1/2)e2+(1/2)].Now we calculate the numerical value: V=π×[8−8×2.71828+(1/2)×2.718282+(1/2)].
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