An aeroplane flying horizontally makes a sound when its angle of elevation w.r.t a person on ground is `theta`. But the sound reached the person, when the aeroplane was just over him. Find the mach.no. of the aeroplane. Also find its speed if speed of sound in air is `'v'_(s)`.

Explanation

To solve the problem step by step, we will analyze the situation involving the airplane and the sound it produces.

### Step 1: Understanding the situation
An airplane is flying horizontally at a certain height, and at an angle of elevation \( \theta \) with respect to a person on the ground, it makes a sound. The sound reaches the person when the airplane is directly overhead.

### Step 2: Define the variables
Let:
- \( V \) = speed of the airplane
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