# The gun o'er the hill

A gun is located at the top of a hill of height $$h$$ above the horizontal plane.It fires two shells with the same velocity $$u$$ at angles $$\alpha$$ and $$\beta$$ with the horizontal.If the shells strike the horizontal ground at the same place then the value of $$h$$ can be expressed as $h=\frac{a u^{2} (1-\tan\alpha \tan\beta)}{g (\tan\alpha+\tan\beta)}$ where $$a$$ is an integer whose value is:

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