Question

Find all solutions in the interval [0, 2π).

7 tan3x - 21 tan x = 0

Answer 1

Factor it first.

Answer 2

You get: \[
(7\tan x)(\tan^2x-3)
\]Then find: \[

(7\tan x) = 0 \\
(\tan^2x-3) =0
\]