A particle just clears a wall of height b at a distance a and strikes the ground at a distance c from the point of projection. The angle of projection is:
Solutions · 1
Official solution
Using the trajectory equation y=xtanα(1−Rx) with range R=c, at x=a, y=b:
\[b=a\tan\alpha\left(1-\frac ac\right)=a\tan\alpha\cdot\frac{c-a}c \implies \tan\alpha=\frac{bc}{a(c-a)}\]
\[\alpha=\tan^{-1}\frac{bc}{a(c-a)}\]