Find the angle between two vector `A=2hati+hatj-hatk andB=hati-hatk.`

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 follow these steps:

### Step 1: Calculate the Magnitude of Vector A
The magnitude of vector \( \mathbf{A} \) is calculated using the formula:
\[ |\mathbf{A}| = \sqrt{A_x^2 + A_y^2 + A_z^2} \]
For \( \mathbf{A} = 2\hat{i} + \hat{j} - \hat{k} \):
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