How do you solve [0,360) Cosx - 2sinx cosx = 0 ??

1 Answer
Nghi N
Mar 6, 2018

#pi/6, pi/2, (5pi)/6, (3pi)/2#

Explanation:

cos x - 2sin x.cos x = 0
cos x(1 - 2sin x) = 0
Either factor should be zero
a. cos x = 0
Unit circle gives 2 solutions:
#x = pi/2#, and #x = (3pi)/2#
b. 1 - 2sin x = 0
sin x = 1/2
Trig table and unit circle give 2 solutions:
#x = pi/6#, and #x = (5pi)/6#

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