how do I solve for this 2π∫ from 0 to 8 (y(√(y/2)-(y/4))dy
I don't know what to do with √(y/2).
taking your brackets to be in their correct places,
let's just consider the ∫ (y(√(y/2)-(y/4))dy
= ∫ ( y^(3/2) / √2 - y^2 / 4 )dy
= (1/√2)(2/5) y^(5/2) - (1/4)(1/3)y^3 <--- check by taking the derivative
take it from there