# Thread: help with a hard trig integration

1. ## help with a hard trig integration

ok, i am almost positive this is going to end up involving an inverse trig function, since thats the section its in

ive been going at it for a while and cant get anything to work

(integral) 1/((x-a)(b-x)) dx b=/=a

it says Hint: x-a= (b-a)(sin^2 u)
i plugged that in, and got little help.. any help is greatly appreciated as always

2. Originally Posted by twostep08
ok, i am almost positive this is going to end up involving an inverse trig function, since thats the section its in

ive been going at it for a while and cant get anything to work

(integral) 1/((x-a)(b-x)) dx b=/=a

it says Hint: x-a= (b-a)(sin^2 u)
i plugged that in, and got little help.. any help is greatly appreciated as always

$\frac{1}{(x-a)(b-x)}=\frac{1}{b-a}\left(\frac{1}{x-a}-\frac{1}{x-b}\right)$

I can't understand what's sine's business here...

Tonio