Question

find exact value using reference angles

cot -53pi/6

Answer 1

It's the same as cot (-150 or -5pi/6) and that's a reference angle of 30 so cot 30 or pi/6 is sqrt (3) and since it's in the 3rd quadrant, it's positive.

Answer 2

cot(-53π/6) = cot(7π/6) = √(3)

Explanation:

Remember that a trig function repeats itself every 2π, so you can add any multiple of 2π to your angle and it'll give you the same answer.

cot(-53π/6) = cot(-53π/6 + 2πk)

= cot(-53π/6 + 2π·5)

= cot(-53π/6 + 10π)

= cot(7π/6)

= [-√(3)/2] / [-1/2]

= √(3)