Question

How do you find the value for `arctan(1)`?

Answer 1

It would be `45^o` or `pi/4rad`

Explanation:

`arctan(1)` means: find the angle that belongs to a ratio of opposite side divided by adjoining side (in a rectangular triangle) of `1`.
Or in other words: where the opposite and adjoining sides are equal.
This only happens in an isosceles rectangular triangle, where both other angles are one half of a right angle, i.e. `45^o` or `pi/4rad`