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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