Projectile without air resistance

[xSPARX]

Homework Statement

Consider a projectile without air resistance. Show
that when the range is maximized, it may be given
in terms of the maximum height

Homework Equations

R = 4hmax

The Attempt at a Solution

I tried looking upon the equation for the vector R but could not understand where 4h came from. Is the max pertaining to velocity =0 ?

 

[ideasrule]

Write out the equation for range. What's the projectile's speed of launch if its launch angle is optimized? Using this speed and the optimal angle, can you calculate maximum height?

 

[xSPARX]

I appreciate the help for this problem :]

 

[xSPARX]

To find out the projectile speed given that the launch angle is optimized is giving me a hassle because the equation for y or x has time in it. Or am i using the wrong equation?

 

[aim1732]

Yes,the formula for max height does not have x,y or t.