Hello, I have 2 questions that I have been stuck on and trouble getting started and need help.

Questions

- In an electrical circuit, voltages are in the form of a sine or cosine wave. Two alternating current waves V1 = 10 sin (50(pi)t) and V2 = 10 cos(50(pi)t) interfere with each other to produce a third wave in the form of V(t) = V1(t) + V2(t) . Find the exact values of the positive number
Aand for theta in [0, 2pi] such that V(t)=A sin(50(pi)t + theta) . Formula for this is A sin x + B cos x = C sin (x+ theta)- The horizontal range, R(theta), of a projectile fired with an initial velocity of 60 meters per second at an angle theta is given by R(theta) = 60^2 sin(theta)cos(theta) / 4.9 , where R(theta) is in Quadrant 1. At what angle must the projectile be fired so that the horizontal range is 280 meters? - Use double-angle identity.

These are the questions, I just need help getting started or If possible you can provide an example of how to solve it.

thank you