Question

How do you use the sum and difference formula to simplify `cot(-(5pi)/12)`?

Answer 1

`-tan (pi/12)`

Explanation:

Use trig unit circle, and property of complementary arcs:
`cot((-5pi)/12) = cot ((7pi)/12 - pi) = cot ((7pi)/12) =`
`= cot (pi/12 + pi/2) = -tan (pi/12)`