`P(1,0,-1), Q(2,0,-3),R(-1,2,0)a n dS(3,-2,-1),` then find the projection length of ` vec PQ and vec R Sdot`

Explanation

To find the projection lengths of the vectors \(\vec{PQ}\) and \(\vec{RS}\), we will follow these steps:

### Step 1: Find the vector \(\vec{PQ}\)

The vector \(\vec{PQ}\) is given by the difference of the position vectors of points \(Q\) and \(P\).

\[
\vec{PQ} = \vec{Q} - \vec{P} = (2, 0, -3) - (1, 0, -1)
...