Question

How do you evaluate `sec(tan^-1(8))` without a calculator?

Answer 1

`sqrt65`

Explanation:

`tan^-1(8)` means the angle whose tan is 8
Draw a right angle triangle with two shorter sides 8 and 1
Mark in `theta` opposite the side length 8.
The hypotenuse is length `sqrt65` -Pythagoras
The sec of `theta` is hypotenuse divided by adjacent