What is the volume of the solid of revolution generated by revolving R about the x-axis?

Let f(x) = e^(-3x/2)
Let R be the region between the graph of f and the x-axis on the interval 0 < x < 1. Find the volume V of the solid of revolution generated by revolving R about the x-axis.

I’ve been trying all night to figure this problem out with no luck at all. Please help!

Use the method of disks.

Draw the region R and a typical disk. This disk has a radius of [e^(-3x/2) - 0] and a thickness of dx. It contribues an increment of volume dV given by

dV = πr²dx = π(e^(-3x/2))² dx
= π e^(-3x) dx

The total volume V is given by

1
∫ π e^(-3x) dx
0

One Response to “What is the volume of the solid of revolution generated by revolving R about the x-axis?”

  1. Use the method of disks.

    Draw the region R and a typical disk. This disk has a radius of [e^(-3x/2) - 0] and a thickness of dx. It contribues an increment of volume dV given by

    dV = πr²dx = π(e^(-3x/2))² dx
    = π e^(-3x) dx

    The total volume V is given by

    1
    ∫ π e^(-3x) dx
    0
    References :

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