SOLUTION: Help with this problem? I need help on how to work out this problem. Thank you! Use a double- or half-angle formula to determine the value of the trigonometric function. sin(

Algebra ->  Trigonometry-basics -> SOLUTION: Help with this problem? I need help on how to work out this problem. Thank you! Use a double- or half-angle formula to determine the value of the trigonometric function. sin(      Log On


   

Question 864341: Help with this problem? I need help on how to work out this problem. Thank you!
Use a double- or half-angle formula to determine the value of the trigonometric function.
sin(27pi/8)
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Help with this problem? I need help on how to work out this problem. Thank you!
Use a double- or half-angle formula to determine the value of the trigonometric function.
sin(27pi/8)
***
Use half-angle formula for sin: sin%28x%2F2%29=%28sqrt%281-cosx%29%2F2%29
sin%2827pi%2F8%29=%2827pi%2F4%29%2F2
27pi%2F4=24pi%2F4%2B3pi%2F4=6pi%2B3pi%2F4=reference.angle of (3pi/4) in quadrant II
cosx=cos%283pi%2F4%29=-sqrt%282%29%2F2

calculator check:
sin(27π/8)≈0-0.9238
exact value=-sqrt%282%2Bsqrt%282%29%29%2F2%29≈-0.9238