Sorry, I don't understand the problem.
Some information is missing . . .
The points lie in a straight line with: .
. . Is line AC horizontal?
A vertical tower is of height and its base
lies in the same horizontal plane as , but not on the line .Really?
The angle of elevation of from are , resp.
(i) Prove that: . . . . . equals WHAT?
Assuming is horizontal, this is all I get:
Code:H o **| * * * | * * * |h * * * | * * * | * * * *O * * α * β α * o - - - o - - - - - - - - - - - o A x B 2x C