Question

How do you find the exact value of `tan ((pi)/2)`?

Answer 1

It does not have an exact value as it is undefined and diverges to `oo`.

Explanation:

The graph of `y=tanx` has a vertical asymptote at `x=pi/2` and so the limit `lim_(x->pi/2)tanx` does not exist.
The graph diverges to `oo` as x approaches `pi/2`.

graph{tanx [-8.89, 8.89, -4.444, 4.45]}