# Thread: Trig Simplification

1. ## Trig Simplification

Originally I had this integrand:
$\int \frac{dx}{x^4\sqrt{x^2+3}}$
http://www.wolframalpha.com/input/?i...8x^2%2B3%29%29
I don't understand how the software came up with $\frac {1}{9}cot^3(u)*csc(u)$
When I simplified it the same way it did I came up with
$\frac{sec(u)}{9tan^4(u)}$

How did wolframalpha simplify it? Or did I just simplify it incorrectly?

2. Originally Posted by WhoCares357
Originally I had this integrand:
$\int \frac{dx}{x^4\sqrt{x^2+3}}$
- Wolfram|Alpha
I don't understand how the software came up with $\frac {1}{9}cot^3(u)*csc(u)$
When I simplified it the same way it did I came up with
$\frac{sec(u)}{9tan^4(u)}$

How did wolframalpha simplify it? Or did I just simplify it incorrectly?
The two expressions are equivalent. Substitute $\tan u = \frac{\sin u}{\cos u}$, $\cot u = \frac{\cos u}{\sin u}$ etc. to see this.

3. Originally Posted by mr fantastic
The two expressions are equivalent. Substitute $\tan u = \frac{\sin u}{\cos u}$, $\cot u = \frac{\cos u}{\sin u}$ etc. to see this.
Thanks.