posted by Dave .
Evaluate the integral of x * sqrt(x-1) from [1,2].
I let u=x-1 and du=1*dx, but then I can't get rid of the x to start integrating?
The answer in the book is 16/15.
u^2 = x-1
2u du = dx
x = u^2+1
= ∫(u^2+1)(u)(2u du)