The angle of elevation of C from A and B are `alpha` and `beta` respectively. B is vertically above A and AB is equal to half the height of C above the level of A. Then, `cot alpha tan beta` is equal to

The angles of elevation of a cliff at a point A on the ground and at a point B100mt vertically above A are alpha are beta respectively.The height of the cliff in metres is

A vertical tower Stands on a horizontal plane and is surmounted by a vertical flag staff of height h.At a point on the plane,the angles of Elevation of the bottom and the top of the flag staff are alpha and beta respectively Prove that the height of the tower is (h tan alpha)/(tan beta-tan alpha)

If the angle of elevation of a cloud from a point h metres above a lake is alpha and the angle of depression of its reflection in the take is beta prove that the height of the cloud is h(tan beta+tan alpha)quad tan beta-tan alpha

If cot(alpha+beta)=0, then sin(alpha+2 beta) is equal to