If R and H represent horizontal range and maximum height of the projectile, then the angle of projection with the horizontal is
tan-1(HR)
tan-1(2HR)
tan-1(4HR)
tan-1(4RH)
Maximum height, H = u2sin2θ2g ------(i)
Horizontal range, R = u2sin 2 θg = 2u2 sin θ cos θg-------------(ii)
Dividing (i) by (ii), we get
HR = tan θ4 or tan θ = 4HR or θ = tan-1(4HR)