cos (x/2) = sin (x+ pi/2) and -33 < x <= -29, what do i do to find x? i know that cos (x/2) = cos x sin (pi/2) + cos (pi/2) sin x equals
cos (x/2) = cos x, and what do i do from now to find the x value?
cos(x) = 2cos^2(x/2) - 1
Hence you have 2cos^2(x/2) - 1 = cos(x/2)
2cos^2(x/2) - cos(x/2) - 1 = 0
(2cos(x/2) + 1)(cos(x/2) -1) = 0
Possible solutions are: cos(x/2) = -1/2 and cos(x/2) = 1
Can you take it from here?
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