# What is the exact value of #cot(-90)# and #csc690#, using unit circle?

##### 1 Answer

Oct 23, 2017

It depends on what you do want to use.

#### Explanation:

I assume that you actually mean to ask about

(There is no nice way to express the exact value of

If you know the following, then there is no need to use the unit circle:

We get

**For the other** we can use

# = csc(330^@-360^@) = csc(-30^@)#

# = 1/sin(-30^@) = 1/(-sin(30^@)) = 1/(-(1/2)) = -2#