Question

What is the exact value of `csc (pi)`?

Answer 1

You cannot get an exact value;
Considering that `csc(x)=1/sin(x)` and that `sin(pi)=0` you get:
`csc(pi)=1/sin(pi)=1/0` which cannot be calculated.
Graphically you have:

Getting near to `pi` makes the `csc` become very big (positively or negatively).