# What are inverse trigonometric functions and when do you use it?

Nov 2, 2014

Inverse trigonometric functions are useful in finding angles.

Example

If $\cos \theta = \frac{1}{\sqrt{2}}$, then find the angle $\theta$.

By taking the inverse cosine of both sides of the equation,

$\implies {\cos}^{- 1} \left(\cos \theta\right) = {\cos}^{- 1} \left(\frac{1}{\sqrt{2}}\right)$

since cosine and its inverse cancel out each other,

$\implies \theta = {\cos}^{- 1} \left(\frac{1}{\sqrt{2}}\right) = \frac{\pi}{4}$

I hope that this was helpful.