Question

Can somebody explain it to me please?​

Answer 1

Range be R and height be h

`\boxed{\sf R=(u^2sin2\theta)/(g)}`

`\boxed{\sf h=(u^2sin^2\theta)/(2g)}`

u=initial velocity

theta is angle of projection.

g=acceleration due to gravity

ATQ

`\\ \sf\longmapsto R=2h`

`\\ \sf\longmapsto (u^2sin2\theta)/(g)=(2u^2sin^2\theta)/(2g)`

Cancelling required ones

`\\ \sf\longmapsto sin^2\theta=sin2\theta`

sin2O=2sinOcosO

`\\ \sf\longmapsto sin^2\theta=2sin\theta cos\theta`

`\\ \sf\longmapsto (sin\theta)/(cos\theta)=2`

`\\ \sf\longmapsto tan\theta=2`

`\\ \sf\longmapsto \theta=tan^(-1)(2)`

`\\ \sf\longmapsto \theta=63.4°`

Done

Option B is correct