How do you integrate int (x+1)/sqrt(x-1) using substitution?

1 Answer
Jul 19, 2016

= 2/3 ( x + 5) sqrt(x-1) + C

Explanation:

int (x+1)/sqrt(x-1) \ dx

we can try simple linear sub u = x-1, x = u+1, dx = du

integral becomes
int (u+2)/sqrt(u) \ du

= int \ sqrt u+2/sqrt(u) \ du which is very doable, just the power rule

= 2/3 u^(3/2) +4 sqrt(u) + C

= 2/3 (x-1)^(3/2) +4 sqrt(x-1) + C

which we can tidy up a bit.....

= (2/3 x- 2/3 +4) sqrt(x-1) + C

= (2/3 x + 10/3) sqrt(x-1) + C

= 2/3 ( x + 5) sqrt(x-1) + C

that's the simplest way i reckon