SOLUTION: using compound angle formula find a) tan 165 (book ans is -2+square root 3) b) sec 165 pls help me am not the ans. thx in adv

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Question 1119175: using compound angle formula find
a) tan 165 (book ans is -2+square root 3)
b) sec 165
pls help me am not the ans.
thx in adv
Answer by ikleyn(52786) About Me  (Show Source):
You can put this solution on YOUR website!
.
tan(165°) = tan(120°+45°) = %28tan%28120%5Eo%29%2Btan%2845%5Eo%29%29%2F%281-tan%28120%5Eo%29%2Atan%2845%5Eo%29%29


    tan(120°) = -sqrt%283%29;  tan(45°) = 1  =============>


= %28-sqrt%283%29%2B1%29%2F%281-%28-sqrt%283%29%2A1%29%29 = %281-sqrt%283%29%29%2F%281%2Bsqrt%283%29%29 = %281-sqrt%283%29%29%2F%281%2Bsqrt%283%29%29 . %281-sqrt%283%29%29%2F%281-sqrt%283%29%29 = %281-2%2Asqrt%283%29%2B3%29%2F%281-3%29 = %284-2%2Asqrt%283%29%29%2F%28-2%29 = sqrt%283%29-2.

Solved.