How do you find int (x-1)/sqrt(x^2-2x)x1x22x?

1 Answer
Nov 10, 2016

sqrt(x^2-2x)+Cx22x+C

Explanation:

I=int(x-1)/sqrt(x^2-2x)dx=1/2int(2x-2)/sqrt(x^2-2x)dxI=x1x22xdx=122x2x22xdx

Substituting u=x^2-2xu=x22x yields du=(2x-2)dxdu=(2x2)dx.

I=1/2int(du)/sqrtu=1/2intu^(-1/2)duI=12duu=12u12du

With the rule intu^ndu=u^(n+1)/(n+1)+Cundu=un+1n+1+C, we see that

I=1/2u^(1/2)/(1/2)+C=u^(1/2)+C=sqrtu+C=sqrt(x^2-2x)+CI=12u1212+C=u12+C=u+C=x22x+C