Question

Find volume of solid generated by revolving parabola y². = 4ax, cut of by latus rectum, about tangent at vertex.

Options

• `(4pia^3)/5`

• `4pia^3`

• `(4pia^2)/5`

• `(4pi)/5`

Answer 1

`(4pia^3)/5`

Explanation:

V = `2int_(y_1)^(y_2) pi  x^2  dy`

= `2pi int_0^(2a) (y^2/(4a))^2  dy`

= `(2pi)/(16a^2) (y^5/5)_0^(2a)`

= `(4pia^3)/5`