Find the angle between the vectors
` vec A = hat I + 2 hat j- hat k` and ` vec B =- hat I + hatj - 2 hat k`.

Explanation

To find the angle between the vectors \( \vec{A} = \hat{i} + 2\hat{j} - \hat{k} \) and \( \vec{B} = -\hat{i} + \hat{j} - 2\hat{k} \), we can use the dot product formula. The angle \( \theta \) between two vectors can be calculated using the formula:

\[ \vec{A} \cdot \vec{B} = |\vec{A}| |\vec{B}| \cos \theta \]

### Step-by-Step Solution:

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