I'm finding the exact values of the following expressions.

1. $\displaystyle sin(\frac{-7pi} {3})$ = $\displaystyle \frac{\sqrt3}{2}$

2. $\displaystyle sec(\frac{-21pi}{4})$= $\displaystyle \frac{-\sqrt1}{2}$

3. $\displaystyle cot(\frac{25pi}{2})$=Undefined

4. $\displaystyle csc(\frac{-101pi}{6})$= $\displaystyle -1$

5.$\displaystyle cos({-126Pi})$= Undefined

Thank You

Jason