# Math Help - trigonometric substitution-another problem

1. ## trigonometric substitution-another problem

I hope its ok I put it as an attachment- I'm really slow/bad at typing in TEX...

but basically I got stuck where I integrate 1/sec^2theta...I feel like something went wrong when I got this...

2. Originally Posted by bcahmel

I hope its ok I put it as an attachment- I'm really slow/bad at typing in TEX...

but basically I got stuck where I integrate 1/sec^2theta...I feel like something went wrong when I got this...
You are fine! You just need to draw a right triangle.

From the above diagram you can see that

$\displaystyle \sin(\theta)=\frac{x}{\sqrt{x^2+16}}$ and
$\displaystyle \cos(\theta)=\frac{4}{\sqrt{x^2+16}}$

Now just sub all of this in

3. thank you! I was convinced i had it wrong...but there are so many steps to these problems.