For any two vectors `veca and vecb` prove that `|veca+vecb|lt+|veca|+|vecb|`

Explanation

To prove that for any two vectors \(\vec{a}\) and \(\vec{b}\), the inequality \(|\vec{a} + \vec{b}| < |\vec{a}| + |\vec{b}|\) holds, we can follow these steps:

### Step 1: Start with the expression for the magnitude of the sum of two vectors.
We know that the magnitude of the sum of two vectors can be expressed as:
\[ |\vec{a} + \vec{b}|^2 = (\vec{a} + \vec{b}) \cdot (\vec{a} + \vec{b}) \]

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