Question #e30c5

1 Answer
Nghi N.
Jul 25, 2015

Solve 2sin 3x.cos x - cos x = 0
Ans: #(pi)/2; (3pi)/2; (pi)/18; and (5pi)/18#

Explanation:

2sin 3x.cos x - cos x = 0
cos x (2sin 3x - 1) = 0
a. cos x = 0 --> #x = (pi)/2# and #x = (3pi)/2#

b. sin 3x = 1/2 --> 3x = pi/6 --> #x = pi/18# and
#3x = (pi - pi/6) = (5pi)/6# --> #x = 5pi/18#

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