Question

What does `-cos(arctan(6))-2csc(arccos(5))` equal?

Answer 1

arc cos 5 is an invalid arc cosine.

Explanation:

arc cos 5 in the expression is the angle whose cosine is 5.

For any a. `-1 <= cos a <= 1`.

So, there is no a for which `cos a = 5 > 1.`