How do you simplify this 2 cos ^3 x - cos x = cos x ?

1 Answer
Mar 18, 2018

#color(green)(x = 0 + 2pin, pi + 2pin#

Explanation:

#2cos^3x - cos x = cos x#

# cancel (2cos^3x)^color(red)(cos^2x) = cancel(2 cos x)^color(red)1#

#cos^2x = 1#

#cos x = +- 1#

#x = 0# or #pi#

General solution

#x = 0 + 2pin, pi + 2pin#