Use the unit circle to find cot 225°

Question

asked Sep 13, 2020 170k views

1 Answer

Febin Mathew · Answer 1 · 2020-09-17T10:32:49+0000

Answer:

$\cot 225\degree=1$

Explanation:

We want to use the unit circle to find the value of
$\cot 225\degree$ .

Note that
$225\degree$ is in the third quadrant.

This makes an angle of
$45\degree$ with the positive x-axis.

$\cot 225\degree=(\cos225\degree)/(\sin225\degree)$

$\cot 225\degree=(-\cos45\degree)/(-\sin45\degree)$

On the unit circle;

$\cos 45\degree=\sin 45\degree=(√(2) )/(2)$

$\cot 225\degree=(-(√(2))/(2))/(-(√(2))/(2))$

$\cot 225\degree=1$