Posted by Leah on Monday, June 11, 2012 at 5:03am.
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  Steve, Monday, June 11, 2012 at 11:29am
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