Mathematics
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Find sin x/2, cos x/2, and tan x/2, if cos x = -12/13, 180 degrees is less than x which is less than 270 degrees

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sassymissy

cos x = -12/13 sin x = -sqrt(13^2 - 12^2) / 13 = -5/13 tan x = 5/12 tan x/2 = (1 - cos x) / sin x = 1 - (-12/13) / -5/13 = 25/13 * -13/5 = -5 2sin^2 x/2 = 1 - cos x = 1 - (-12/13) = 25/13 sin^2 x/2 = 25/13 / 2 = 25/26 sin x/2 = 5/√26 sin x/2 / cos x/2 = tan x/2 cos x/2 = sin x/2 / tan x/2 = 5/√26 / -5 = -1/√26 sin x/2 = 5/√26 cos x/2 = -1/√26 tan x/2 = -5

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