Show that each of the given three vectors is a unit vector: `1/7(2 hat i+3 hat j+6 hat k),1/7(3 hat i-6 hat j+2 hat k),1/7(6 hat i+2 hat j-3 hat k)`Also, show that they are mutually perpendicular to each other.

Explanation

To show that the given vectors are unit vectors and mutually perpendicular, we will follow these steps:

### Step 1: Define the Vectors
Let the three vectors be defined as follows:
- \( \mathbf{A} = \frac{1}{7}(2\hat{i} + 3\hat{j} + 6\hat{k}) \)
- \( \mathbf{B} = \frac{1}{7}(3\hat{i} - 6\hat{j} + 2\hat{k}) \)
- \( \mathbf{C} = \frac{1}{7}(6\hat{i} + 2\hat{j} - 3\hat{k}) \)

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