# What does sec(arccos(2))+3cot(arctan(-1)) equal?

Apr 12, 2016

As absolute value of cos x = |cos x| $\le 1$, there is no x for which cosine is 2.

#### Explanation:

If x = arc cos (2), cos x = 2 > 1.
So, arc cos(2) is unreal..

The second term = 3cot(arc cot(1/(-1))=3cot(arc cot(-1))=3(-1)=-3

Successive operations by 'cot' over 'arc cot' amounts to multiplication by 1..