SOLUTION: value of sin(a/2) if cos a=2/3 and (0<a<90)

Algebra ->  Trigonometry-basics -> SOLUTION: value of sin(a/2) if cos a=2/3 and (0<a<90)      Log On


   

Question 778053: value of sin(a/2) if cos a=2/3 and (0
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
value of sin(a/2) if cos a=2/3 and 0 < a < 90º
use half-angle formula for sin:

..
check:
cos(a)=2/3
a≈48.19º
a/2≈24.09º
sin(a/2)≈sin(24.09º)≈0.4082
exact value=√6/6≈0.4082