Posted by AJ on .
If
sin(x) = 1/3 and sec(y) = 29/21
, where x and y lie between 0 and π/2, evaluate the expression using trigonometric identities. (Enter an exact answer.)
cos(2y)

Math 
Steve,
cos(y) = 21/29
cos(2y) = 2cos^2(y)  1 = 2(21/29)^2  1 = 41/841