volume of revolution formulae

Question 1

what is the formula for the volume of revolution around the y axis

Answer 1

V = π∫[f(y)]2dy

limits are the y values of the bottom and top of volume of revolution

can rearrange function of y in terms of x (f(x)) to find f(y)

Question 2

what is the formula for the volume of revolution around the x axis

Answer 2

V = π∫[f(x)]2dx

limits are x values