trig
posted by Priya .
If sin theta = x and pi/2 is less than or equal to theta less than or equal to pi/2, find sin 2theta and cos 2theta in terms of x.
Is it alright if I recommend you to my classmates tommorow? YOu seem to know more than my professor!

follow the two formulas I pointed out to you in
http://www.jiskha.com/display.cgi?id=1209674791
Many of us here are retired teachers or profs.
I am not on here on any regular basis, all of us are volunteers.