# Thread: integration help on question

1. ## integration help on question

integrate
$

\int (7sec(9-8x)tan(9-8x)) dx

$

any help much appreciated

2. Originally Posted by jvignacio
integrate
$

\int (7sec(9-8x)tan(9-8x)) dx

$

any help much appreciated
First make the substitution u = 9 - 8x. Then note that sec(u) tan(u) = sin(u)/cos^2(u). So make the substitution w = cos(u).

Try this. Show your working and where you get stuck if you still have trouble.