A projectile is launched at an angle α from the edge of a cliff of height H above sea level. If it falls into the sea a distance D from the base of the cliff, prove that its maximum height above sea level is H + [(Dtan α)^2]/4(H + Dtan α) Newtons equations of linear motion in the i/j plane. Well, I understand that the max height is at a height H + (something) with that something being Sjmax, when Vj=0. Ive got my Sjmax = (usin α)^2/ 2g This is where i get a little stuck... Ive tried a couple of things but the fact that its a cliff is making my reasoning wrong, if it wasnt a cliff, you could also say that the max vertical height is obtained when the horizontal displacement is D/2, the christmas break has made the old mind a little blunt... Any hints? Thanks so much in advance.