PLease help with this homework

Question

Consider the function y(x) = − sqrt( 1 − x^2), the volume of the solid of revolution about the x-axis is :

a. Undefined

b. π

c. 4π/3

d. Cannot be solved using known techniques

Answer 1

y(x) = -√(1-x²)

V= π∫_a^by²dx = π∫_-1¹ 1-x² dx = π[x-x³/3]_-1¹ = π[1-1/3-(-1+1/3)] = 4π/3

Answer C.