In a projectile motion, the horizontal range and the maximum height attained by the projectile are equal .

A) what is the launch angle?
B) If everything else slays the same , how should the launch angle, ¦È0, of a projectile be changed for the range of the projectile to be halve?

3 answers

be halved??
recall that

range = v^2/g sin(2θ)
height = v^2/g sin^2(θ)

so, solve for θ

an excellent discussion of trajectories for all your problems can be found at

https://en.wikipedia.org/wiki/Trajectory
thanks a lot sir@Steve