math (trig)
posted by Jeff .
if cos 2 theta = (1/3) and theta is in Quadrant 2, find sin theta, cos theta, tan theta, and draw triangle theta

1/3 = cos 2theta = 1  2 sin^2 theta
2 sin^2 theta = 4/3
sin theta = sqrt(2/3)
cos theta = sqrt(1  2/3) = sqrt(1/3)
(minus since theta must be in quadrant 2)
tan theta = sqrt2
theta = 125.26 degrees
You draw the figure