Prove that `( vec a- vec b)xx( vec a+ vec b)=2( vec axx vec b)` and interpret it geometrically.

Explanation

To prove that \((\vec{a} - \vec{b}) \times (\vec{a} + \vec{b}) = 2(\vec{a} \times \vec{b})\), we will follow these steps:

### Step 1: Write down the expression
We start with the expression we want to prove:
\[ (\vec{a} - \vec{b}) \times (\vec{a} + \vec{b}) \]

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