Algebra II
posted by Lucy on .
Find the exact value of sin(theta/2) if cos theta = 2/3 and 270 degrees<theta<360 degrees.
Answer: sqrt6/6

half angle between 135 and 180 which is quadrant 2
half angle formula in quad 2
sqrt [(1cos t)/2 ]
sqrt [ (1/3) /2 ]
sqrt (1/6)
sqrt 1/sqrt 6
sqrt 6/6 agree