[" es above a lake is a and the "],[" ove that the distance of the "]

The angle of elevation of a cloud from a point 'h' metres above a lake is alpha and the angle of deprssion of its reflection in the lake is beta . Pover that the distance of the cloud from the point of observation is (2hsecalpha)/(tanbeta-tanalpha) .

If the angle of elevation of a cloud from a point h metres above lake is alpha and the angle of depression of its reflection in the lake be beta , prove that the distance of the cloud from the point of observation is (2 h sec alpha)/(tan beta - tan alpha)

The angle of elevation of a stationar cloud from a point 2500 m above a lake is 15^(@) and from the same point the angle of depression of its reflectin in the lake is 45^(@) . The height (in meters) of the cloud above the lake, given that cot15^(@)=2+sqrt3 , is

The angle of elevation of an aeroplane as observed from a point 30 m above the transparent water-sur- face of a lake is 30^(@) and the angle of depression of the image of the aeroplane in the water of the lake is 60^(@) . The height of the aeroplane from the water- surface of the lake is: