If sin x = 1/3 and sec y = 5/4, where x and y lie between 0 and pi/2, evaluate the expression.
2siny = 2siny*cosy?
cos2y = cos^2 y - sin^2 y?
The Attempt at a Solution
I think sin2y goes to 2siny*cosy. I know what sin x is but how do I find sin y? The answer should be 24/25 for siny, but not sure how to get it. Not sure what the answer is or how to get it for cos2y.