Hello, dojo!

Sorry, I don't understand the problem.

Some information is missing . . .

The points $\displaystyle A,B,C$ lie in a straight line with: .$\displaystyle AB=x,\;BC=2x$

. . Is line AC horizontal?

A vertical tower $\displaystyle OH$ is of height $\displaystyle h$ and its base $\displaystyle O$

lies in the same horizontal plane as $\displaystyle ABC$, but *not on the line* $\displaystyle ABC.$ .Really?

The angle of elevation of $\displaystyle H$ from $\displaystyle A,B,C$ are $\displaystyle \alpha,\;\beta,\;\alpha$, resp.

(i) Prove that: .$\displaystyle h^2\left(\cot^2\alpha - \cot^2\beta\right)$ . . . . equals *WHAT?*

Assuming $\displaystyle AC$ is horizontal, this is all I get:

Code:

H
o
**| *
* * | *
* * |h *
* * | *
* * | *
* * *O *
* α * β α *
o - - - o - - - - - - - - - - - o
A x B 2x C