## Answers

#### Explanation:

Cosx=-1, or, cosx=1/2#.

The solutions are

#### Explanation:

You can use this altered Pythagorean identity:

Now here's the actual problem. The strategy is to get everything in terms of

Here's a unit circle to remind us of some cosine values:

This means that:

Therefore, the solutions are

#### Explanation:

Since,

Cos(3/2x)=0 rArr 3/2x=90^@, 270^@#.

Altogether, **as Before!**