​​Sketch a unit circle. In your circle, sketch an angle between $0$ and $2\pi$ that has:  

1. A positive cosine and a negative sine.

   Possible Answer (a):

    

2. A sine of $-0.5$.

   Possible Answer (b):

   

3. A negative cosine and a negative sine.

   Possible Answer (c):

   

4. A cosine of about $-0.9$ and a sine of about $0.3$.

   Possible Answer (d):

   

5. Could an angle have a sine equal to $0.9$ and cosine equal to $0.8$? Give an angle or explain why not.

   Hint (e):

   Does $\sin^2(θ)+\cos^2(θ)=1$?