1. The problem statement, all variables and given/known data Hey I'm doing something really stupid it is really pissing me off why I can't figure it out. 3. The attempt at a solution Evaulate the integral : ∫ x(1-x)^1/2 I tried with substitution. u = 1-x , -du = dx and x = 1-u ∫ (1-u)(u)^1/2 I just tried to simplify it some. ∫ (u^1/2-u^3/2) -du -∫ u^1/2 du +∫ u^3/2 du integrate I got (-2/3)u^ 3/2 + (2/5)u^5/2 (-2/3)(1-x)^ 3/2 + (2/5)(1-x)^5/2 My book got (-2/15)*2+3x)(1-x)^3/2 + C I'm lost. Thanks for the help.