# Math/Trig

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How would I evaluate these trig functions without using a calculator? U:

sin(-13π/6)
cot 11π/6
cot(-14π/4)
sec 23π/6

Thanks in advance ^^; and if you'd tell me step by step on how to do problems like these I'd be grateful :D

• Math/Trig -

sin(-θ) = -sinθ
sin(θ±2kπ) = sinθ
so, sin(-13π/6) = sin(-π/6) = -1/2

tan(θ±kπ) = tanθ -- same for cot
cot(11π/6) = cot(-π/6) = -cot(π/6) = -√3

cot(-14π/4) = cot(2π/4) = cot(π/2) = 0

sec(23π/6) = sec(-π/6) = √3/2

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