Let represent any nonzero vector. Why is a unit vector, and what is its direction? If ? is the angle thamakes with the + x -axis, explain why is called the direction cosine for that axis.

Solution to 21DQ Here in the first part of the solution we would enquire about Unit Vector and its direction.In the second part we would see why(A) .i is a direction cosine in that axis. PART 1 Step 1. Mathematically a vector is defined as a dot product of its magnitude and its direction. =|A|.A Here A t he component that gives the direction of the vecto. he magnitude is given by | |