How do I do this?

Question

Evaluate the trigonometric by using the quadrant and the reference angle to determine the sign and absolute value. 

 

sin(13pi/4) 

Answer 1

Hi Ana,

 

you have 13∏/4.

You know you can write it as 12∏/4 + 1∏/4

The 12∏, when it comes to sin, cos, tan valuse is equal to zero degree because when you complete a circle you are right back where you started.

Now all you have left is∏/4 which is equal to 45°.

 

Can you finish it form here?