1. The problem statement, all variables and given/known data Hey guys, this is my first post and of course first question to ask of calculus Alright well I had this test and we had this very difficult question that I could not solve, it was in the hardest section. The question is as follows: A projectile thrown over level ground, at an angle x to the ground, has a range R given by R = (v^2 / g)(sin2x), where v is the initial speed, in meters per second, and g = 9.8m/s^2. Determine the angle of proection x for which the range is maximum. 2. Relevant equations So I began to isolate for v^2 and then use log differentiation. R(g) = v^2(sin2x) v^2 = Rg / sin2x 3. The attempt at a solution R = (v^2 / g)(sin2x) R = ((v^2)(sin2x) / g) ln R = ln v^2 + ln Sin2x - ln g dR / dx = [(1 / v^2) + (1 / sin2x) - (1 / g)] (v^2(sinx) / g) So im pretty sure that derrivative is right but as of this i am clueless on what to do. Any help is really appreciated, even a guideline so I could figure out the rest myself. Thanks.