# Math Help - Volume of revolution

1. ## Volume of revolution

Find the volume of the solid formed when the are bounded by the curve y = 1+ sqrt(x) and the x-axis for 0<x<4 (and equal to) rotated one revolution about the y-axis

Thank you to anyone who can help me with this question. =)

2. Originally Posted by christina
Find the volume of the solid formed when the are bounded by the curve y = 1+ sqrt(x) and the x-axis for 0<x<4 (and equal to) rotated one revolution about the y-axis

Thank you to anyone who can help me with this question. =)
Hey mate,

the Volume generated by rotating a function f(x) about the x-axis between
x = a and b is given by

V = pi * int ( f(x)^2 dx , x = a to b )

here however you want to rotate about the y-axis, i.e.
V = pi * int (g(y)^2 dy , y = a1 to b1)

so you need to find the alternative form g(y) (hint rearrange y = 1 + sqrt(x) into the form x = g(y) ) and its altered bounds { hint a1 = f(a)...}

please post if you require any further help.