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## Homework Statement

A projectile is to be launched so as to go from A to B [which are respectively at the bases of a double inclined plane having angles [itex]\alpha[/itex] and [itex]\beta[/itex] as seen in the figure] and just barely miss a pole of height [itex]H[/itex] that is located at the tip. If the distance between A and B is D, find the angle with the horizontal at which the projectile should be launched.

[PLAIN]http://b1111.hizliresim.com/r/k/llf5.jpg [Broken]

## The Attempt at a Solution

[PLAIN]http://b1111.hizliresim.com/r/k/llds.jpg [Broken]

I found [itex]h=\frac{D\tan\alpha\tan\beta}{\tan\alpha+\tan\beta}[/itex]

and I considered a particle which is at B is falling free.And Vo vector aimed to point B when t=0 , so they must collide at [itex]t=t_{collide}[/itex] and at top of the H.

Then i wrote [itex]\tan\phi=\frac{1/2gt_{collide}^2+H+h}{\frac{D\tan\beta}{\tan\alpha+\tan\beta}}[/itex]

and i found

[itex]\phi= \tan^-1(\frac{(1/2gt_{collide}^2+H)(\tan\alpha+\tan\beta)+D\tan \alpha \tan\beta}{D\tan\beta})[/itex]

Is my answer is correct ? and are there any solutions for conditions which are before reaching maximum height and minumum height ?

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