# Solved Problems-1

Problem-1
1. Two vectors are represented by . Find the dot and cross products and the angle between the vectors. Show that  is at right angles to .
2. If , find  at the point (1, -2, -1).
Solution

1. âˆ´

âˆ´

Now,
For  to be at right angles to  should be zero.

(Proved)
1.
At the point (1, -2, -1), the gradient is given as,