Question

What is `Arctan (-3/4 )`?

Answer 1

`arctan(-3/4) ~= -0.6435` (radians)`~= -36.87^o`

Explanation:

Consider a 3-4-5 triangle. Let `alpha` designate the smallest angle in this triangle.

Then:
`arctan(-3/4) = -alpha`

There is no nice expression for `alpha` as a multiple of `pi` or number of degrees.