# integral help

• May 22nd 2007, 10:50 AM
viet
integral help
$\int\frac{cos(x)}{1+sin(x)} dx$

i need a little help evaluating this problem
• May 22nd 2007, 11:27 AM
Jhevon
Quote:

Originally Posted by viet
$\int\frac{cos(x)}{1+sin(x)} dx$

i need a little help evaluating this problem

Use substitution:

Let $u = 1 + \sin(x)$

if you need further assistance, just ask. I'm dying to get practice with LaTex anyway
• May 22nd 2007, 12:09 PM
viet
i guess its a two stepper thanks
• May 30th 2007, 11:53 AM
Krizalid
$\int {\frac{{\cos x}}
{{1 + \sin x}}\,dx} = \int {\frac{{(1 + \sin x)'}}
{{1 + \sin x}}\,dx} = \ln \left| {1 + \sin x} \right| + c$

It's useful remember that $\int {\frac{{f'(x)}}
{{f(x)}}\,dx} = \ln \left| {f(x)} \right| + c$