# Question #265f1

##### 2 Answers

#### Explanation:

Use the double angle formula

to rewrite the equation in the form

Substituting

Since

Thus, either

#### Explanation:

Starting with

Add

Square both sides to obtain

Multiply both sides by 2, then put everything on one side:

You've essentially got a simple quadratic equation to factor now. If

=>

So

Like solving for the zeros in any quadratic equation, set each factor equal to zero to find the solutions:

We know from the unit circle that

The next factor:

Likewise, the unit circle shows us that

So,

Or in degrees: