Use the unit circle to find cot(-180)

Question

asked Jan 6, 2020 179k views

2 Answers

Kunemata · Answer 1 · 2020-01-11T14:34:40+0000

if you don't have a Unit Circle, this is a good time to get one, you can find many online.

Check the picture below.

so, let's notice that, -180° has a positive counterpart angle of 180°, they both land on the same spot, thus cot(-180°) is the same as cot(180°).

$\bf cot(-180^o)\implies cot(180^o)\implies \cfrac{cos(180^o)}{sin(180^o)}\implies \cfrac{-1}{0}\implies und efined$