Question

for what numbers theta is f(theta)= cot theta not defined?

Answer 1

We know that when we divide by 0, it isn't defined and as cot(theta)=1/tan(theta) we are looking for values of tan(theta) that equal 0. Find tan^-1(0) and you have your answer (make sure you pick all values in your interval, or specify a set).

Answer 2

Could you detail that a little more? I just don't understand the concept.

Answer 3

Sure! Do you agree that 1/x isn't defined when x=0?