Find the angle between two vectors `A= 2 hat i + hat j - hat k` and `B=hat i - hat k` .

Explanation

To find the angle between the two vectors \( \mathbf{A} = 2 \hat{i} + \hat{j} - \hat{k} \) and \( \mathbf{B} = \hat{i} - \hat{k} \), we can use the dot product formula. Here are the steps to solve the problem:

### Step 1: Calculate the dot product of vectors A and B
The dot product \( \mathbf{A} \cdot \mathbf{B} \) is calculated as follows:

\[ \mathbf{A} \cdot \mathbf{B} = (2 \hat{i} + \hat{j} - \hat{k}) \cdot (\hat{i} - \hat{k}) \]
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