Vectors p=2i−3j+k and q=i+4j−2k are fixed. A third vector is formed as r=p+pq, where p is a real parameter.
a. (i) Find the value of p for which r is perpendicular to p−q.
b. (ii) For the value of p obtained in part (i), calculate ∣r∣.
c. (iii) Show that, for this value of p, the vectors r and q are not parallel.