# How do you evaluate arctan(-1)?

Ans: $\frac{3 \pi}{4} \mathmr{and} \frac{7 \pi}{4}$
tan x = - 1 --> $x = \frac{3 \pi}{4}$ and $x = \frac{3 \pi}{4} + \pi = \frac{7 \pi}{4}$