Prove that Trigonometry Relation #04

Prove that:

Evaluate: Trigonometry Relation #02
Two poles of equal heights are standing opposite to each other
Prove that Trigonometry Relation #03
The angles of depression of the top and bottom of a building 50 metres high
As observed from the top of a 100 m high light house from the sea-level, the angles of depression of two ships
Prove that Trigonometry Relation #05
Evaluate: Trigonometry Relation #01
If tan 2A = cot (A - 18°), where 2A is an acute angle