Show that `(veca-vecb)xx(veca+vecb)=2vecaxx vecb` and give a genometrical interpretation of it.

Explanation

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

### Step 1: Expand the left-hand side using the distributive property of the cross product.
We start with the expression:
\[ (\vec{a} - \vec{b}) \times (\vec{a} + \vec{b}) \]
Using the distributive property, we can expand this as follows:
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