Question

Verify the identity.


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

Answer 1

True

Explanation:

assuming that you meant to write

cot (x-π//2) = - tan x

the identity is TRUE because,

- you can graph cot (x-π//2) and - tan x, and see that the graphs overlap

OR

-you solve for cot (x-π/2)

useful to know is that :

cot x=1/tan x, tan x = sin x/cos x,

cos(x) =cos(-x), sin(-x) = -sin x,

cos(π/2 -x) =sin x, sin (π/2-x) =cos x

cot (x-π/2) = 1/tan (x-π/2) , yet tangent is sin x/cos x

cot (x-π/2) = cos (x-π/2) /sin (x-π/2) , factor -1

cot (x-π/2) = cos -(π/2-x) /sin -(π/2-x), use facts: cos(x) =cos(-x), sin(-x) = -sin x

cot (x-π/2) = cos (π/2-x) / -sin (π/2-x), use cos(π/2 -x) =sin x, sin (π/2-x) =cos x

cot (x-π/2) = sin x / -cos x , again sin x /cos x = tan x

cot (x-π/2) = -tan x