# Circular Funtions questions, Will award best answer!?

evaluate each expression. (exact values only)

1. sin(18pi) = ?

2. csc(13pi/4) = ?3. sec(7pi/2) = ?4. sec(5pi/3) = ?5. cot(-11pi/2) = ?

Update:

don't mind the 1. 2. 3. 4. 5. before each question, tried spacing it out more but ended up like that.

### 1 Answer

Relevance

- 6 months agoFavorite Answer
1. sin(x) when x is a multiple of 2pi is always 0. therefore sin(18pi) = 0

2. csc(13pi/4) = csc( 3pi+pi/4) = -csc(pi/4) = -sqrt(2)

3. sec(7pi/2) = sec(3*pi/2+pi/2) = -sec(pi/2) = -1

4. sec(5pi/3) = sec(pi+2pi/3) = -sec(2pi/3) = -2sqrt(3)/3

5. cot(-11pi/2) = cot(-5pi+pi/2) = -cot(pi/2) = non defined

Still have questions? Get your answers by asking now.