Question

Use the unit circle to find cot 225°

Answer 1

`\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`