Solve 2sinxcosx-sqrt2cosx=0 for 0 <=x<=360degree?

1 Answer
Nghi N
May 17, 2018

#pi/4; pi/2; (3pi)/4; (3pi)/2#

Explanation:

#2sin x.cos x - sqrt2cos x= 0#
#cos x(2sin x - sqrt2) = 0#
Either factor should be zero:
a. cos x = 0
Unit circle give 2 solutions for x:
#x = pi/2#, and #x = (3pi)/2#
b. #2sin x - sqrt2 = 0#
#sin x = sqrt2/2#
Trig table and unit circle give 2 solutions for x
#x = pi/4#, and #x = (3pi)/4#

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