SOLUTION: sin (x+ 1/2 pi)=0

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Question 722263: sin (x+ 1/2 pi)=0
Answer by DrBeeee(684) About Me  (Show Source):
You can put this solution on YOUR website!
The quick answer is
(1) sin(x+90) = cos(x)
The longer answer can be obtained the trig identity for the sum of two angles.
(2) sin(a+b) = sin(a)*cos(b) + cos(a)*sin(b)
Use x for a and 90 for b we get
(3) sin(x+90) = sin(x)*cos(90) + cos(x)*sin(90) or
(4) sin(x+90) = sin(x)*0 + cos(x)*1 or
(5) sin(x+90) = cos(x)