Unclear About Undefined Angles (Trig)?

Question

The question is: If 0 is greater than or equal to theta, and theta is < 2pi, for what angles theta, if any, is tangent theta undefined?

Answer 1

Tan 90 is undefined.

Answer 2

Trig functions become undefined for an angle when when

ever the function as defined as a ratio of two other trig

functions and the DENOMINATOR EQUALS ZERO.

division by zero is prohibited in math.  For the function

y= tan Θ  since tanΘ = sin Θ / cos Θ the function becomes

undefined for any angle where cos Θ = 0 .  Between

0 and 2π  that happens at π/2 and 3π/2