Question

Prove or disprove the identity. If you find the identity is true, state the first line of the proof. If you find the identity is false, write the correct equation by replacing the right side.

sin x cos x tan x cot x = 1

A) the identity is true. sin x cos x tan x cot x = cos x
B) the identity is true. sin x cos x tan x cot x = sin x tan x
C) the identity is false. sin x cos x tan x cot x = sin x cos x
D) the identity is false. sin x cos x tan x cot x = sin x

Answer 1

sin x cos x tan x cot x

Change to sin's cos's:-

= sin x cos x sin x cos x
------- -------
cos x sin x

= sin x cos x

C is correct