1) The angle of elevation of a cloud from point h metres above the surface of a lake is x and the angle of depression of its reflection in the lake is y . Prove that the height of the cloud above the lake is h(tan y+tan x)/(tan y-tan x)

2)

A ladder rests against a vertical wall at an inclination x to the horizontal. Its foot is pulled away from the wall through a distance p so that its upper end slides a distance q down the wall and then the ladder makes y to the horizontal. Show that

p/q=(cos y-cosx)/(sin x- sin y)