The volume of the solid formed by rotating the area enclosed between the curve `y^(2)=4x,x=4` and x = 5 about X-axis is (in cubic units)

Options

A. `18 pi`
B. `36 pi`
C. `9 pi`
D. `24 pi`

Answer

A

Explanation

Volume of the solid `= int_(4)^(5) pi y^2 dx`
`= pi int_(4)^(5) 4x dx`
`= 4pi [ (x^(2))/(2)]^(5)`
`= 2x (25-16)`
`= 18 pi` cu unit