If ` vec a , vec b` are the position vectors of the points `(1,-1),(-2,m),` find the value of `m` for which ` vec a` and `vec b` are collinear.

Explanation

To find the value of \( m \) for which the position vectors \( \vec{a} \) and \( \vec{b} \) are collinear, we can follow these steps:

### Step 1: Define the position vectors
The position vectors of the points are given as follows:
- For point \( A(1, -1) \):
\[ \vec{a} = 1 \hat{i} - 1 \hat{j} = \hat{i} - \hat{j} \]
...