Question

How do you find the exact value of sec (π/2)?

Answer 1

It is undefined.

Explanation:

By definition of trig ratios, `sec(pi/2)=1/(cos(pi/2))`

`=1/0`, which is undefined.

If we draw the graph of `y=sexc` we see that at `x=pi/2` there is a vertical asymptote and hence no output y-value.
That is, `lim_(x->pi/2)secx` does not exist.

graph{secx [-10, 10, -5, 5]}