Trig exact values

[ChaoticLlama]

This was a question that someone gave to me and it's been bugging me for a while

what is the exact value of
sin((3pi)/8)

 

[tkhunny]

sin((3pi)/8)

sin(3pi/8) = sin((3pi/4)/2) = sqrt((1/2)*(1-cos(3pi/4)))

Are we getting closer?

You have to worry about the signs. What quadrant are we in at 3pi/8?