Plot
this function with given values of Vo, d, and h vs x=0 to pi/3 radians.
Where it crosses the X axis is the angle solution in radians.
Vo = given initial (launch) speed feet/sec
d = horizontal distance from launch point to goal, feet
h = vertical height from launch point to goal, feet
Example solution for
f(40,20,8) => 0.607 radians = 34.8 degrees