# Question #96293

##### 1 Answer

On the domain,

Or, in degrees;

On the domain,

#### Explanation:

You are going to need to use the pythagorean identity (

As,

Combining like terms;

Moving all of the information to the left of the equality yields;

The next clever piece of maths comes because you will need to factorise this expression. So what we do is substitute a variable in for the trigonometric ratio.

i.e. let

Which we can factorise using the difference of perfect squares.

By the null factor law we can conclude that

So, on the domain,

Or, in degrees;

On the domain,

I hope that helps :)