Find the angle between the lines
`vecr=3hati-2hatj+6hatk+lamda(2hati+hatj+2hatk)` and `vecr=(2hatj-5hatk)+mu(6hati+3hatj+2hatk)`.

Explanation

To find the angle between the given lines, we can follow these steps:

### Step 1: Identify the direction vectors of the lines
The first line is given by:
\[ \vec{r} = (3\hat{i} - 2\hat{j} + 6\hat{k}) + \lambda(2\hat{i} + \hat{j} + 2\hat{k}) \]
The direction vector \( \vec{b_1} \) for this line is:
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