1. The problem statement, all variables and given/known data Show that the launch angle θ is given by the expression: θ=tan-1(4hmax/R) where hmax is the maximum height in the trajectory and R is the range of the projectile. 2. Relevant equations hmax=vi2sin2(θ)/2g R=vi2sin(2θ)/g 3. The attempt at a solution I am trying to understand the significance of the ratio 4hmax/R. I tried a couple of things, such as substitution and simplifying equations but have gotten nowhere. Can someone give me a tip on how to start this problem?