# Thread: [SOLVED] integration by trig substitution

1. ## [SOLVED] integration by trig substitution

$\int \frac{dx}{sqrt(x^2-4)}$

2. Originally Posted by vinson24
$\int \frac{dx}{sqrt(x^2-4)}$
Note that $\int\frac{\,dx}{\sqrt{x^2-4}}=\int\frac{\,dx}{\sqrt{4\left(\frac{x^2}{4}-1\right)}}=\tfrac{1}{2}\int\frac{\,dx}{\sqrt{\left (\frac{x}{2}\right)^2-1}}$

Can you continue from here?

3. Originally Posted by vinson24
$\int \frac{dx}{\sqrt{x^2-4}}$
alternatively, a trig substitution of $x = 2 \sec \theta$ could work. well, not really alternatively....

4. yes i can thank you