# How do you tell whether the value of sin (-45 degrees) is positive, negative, zero or undefined?

##### 1 Answer

Sep 25, 2015

It's negative.

#### Explanation:

First of all, the sine function is defined all over the real set, so there's no chanche that

Now, you can solve the problem in a geometrical way: since the sine of an angle is the

If you want to see it using the definition, the point in the unit circle identified by a