Question

How do you find the exact value of `sec(pi/4)` using the half angle formula?

Answer 1

Note that `sec(theta) = (1)/(cos(theta))`

Since `sec(pi/4) = (1)/(cos(pi/4))`, and `cos(pi/4) = sqrt(2)/2`, we can see that

`sec(pi/4) = 2/sqrt(2) = sqrt(2)`