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)`.

Explanation

To solve the problem, we need to establish the relationship between the angles of elevation and depression, and the distances involved. Let's break it down step by step.

### Step 1: Understand the Setup
We have a lake, and a point \( A \) that is \( h \) meters above the lake. The cloud is at point \( B \) and its reflection in the lake is at point \( C \). The angle of elevation from point \( A \) to the cloud \( B \) is \( \alpha \), and the angle of depression from point \( A \) to the reflection \( C \) is \( \beta \).

### Step 2: Define the Distances
Let:
- \( AB = l \) (the distance from point \( A \) to the cloud \( B \))
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