Determine the maximum height and range of a projectile fire

Determine the maximum height and range of a projectile fire at a height of 4 feet above the ground with an initial velocity of 600 feet per second and at angle of 45 degree about the horizontal

maximum height :
maximum range:

Maximum height is achieved when Vy = (Vo cos 45)*t -g t = 0 t = (600 sin 45)/g = 424.64 s where g = 32.2 ft/s^2 The height at that time is Vo sin 45 t - (g/2) t^2