The greatest resultant of two vectors `vec P` and `vec Q` is (n) times their least reast resultant. Fiven
`| vec P | gt |vec Q|`. When `theta` is the angle between the two vectors, their resultant is half the sum of the two vectors. Show that,
`cos theta =- (n^(2) +2) // (n n^(2) -1)`.

Explanation

To solve the problem, we need to derive the relationship between the angle θ and the given conditions about the vectors P and Q. Let's go through the solution step by step.

### Step 1: Define the Greatest and Least Resultants
The greatest resultant \( R_{max} \) of two vectors \( \vec{P} \) and \( \vec{Q} \) is given by:
\[ R_{max} = |\vec{P}| + |\vec{Q}| \]
The least resultant \( R_{min} \) is given by:
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