please help me out, and show step by step.
Let sine of theta equals the quantity 3 times radical 2 end quantity over 5 and pi over 2 is less than theta is less than pi period

Part A: Determine the exact value of cos 2θ.

Part B: Determine the exact value of sine of the quantity theta over 2 end quantity period

please help me out and show step by step Let sine of theta equals the quantity 3 times radical 2 end quantity over 5 and pi over 2 is less than theta is less th class=