Range \(R = \frac{u^2\sin 2\theta}{g}\)
For maximum range sin 2θ = 1 or 2θ = 90°
⇒ θ = 45°
For this angle of projection, maximum height
\(H = \frac{u^2\sin^245^\circ}{2g} = \frac{u^2}{4g} = \text{constant}\)
Thus to attain θ = 45°, \(H = \frac{u^2}{4g}\) is necessary
This is why, in long jump, the player takes some height before jumping.