# How do you evaluate #tan^-1(-1)# without a calculator?

##### 1 Answer

Depending upon if the domain is restricted to

#### Explanation:

What you are trying to solve is

Since the problem deals with the inverse tangent, that means we will use the tangent function to solve the problem.

Now let's think about when

If we are rotating an angle and dealing with a right triangle, we know that

Since you are more than likely discussing radians,

Therefore

If the domain is restricted to