### Home > A2C > Chapter 8 > Lesson 8.1.4 > Problem 8-64

8-64.

Sketch a unit circle. In your circle, sketch in an angle that has:

A positive cosine and a negative sine.

A sine of

. A negative cosine and a negative sine.

A cosine of about

and a sine of about . Could an angle have a sine equal to

and cosine equal to ? Give an angle or explain why not.

Use the eTool below to explore these ideas.

Click the link at right for the full version of the eTool: *8-64 HW eTool*