Question

How do you verify the identity `cotx- pi/2 = -tan x`?

Answer 1

Verify `cot (x - pi/2) = - tan x`

Explanation:

On the trig unit circle,

`cot ( x - pi/2) = - cot (x + pi/2)`

`cot (x + pi/2) = tan x` because they are supplementary arcs, then:

`cot (x - pi/2) = - tan x`