Given the vectors: A=(1,2,3) and B=(4,3,1).

a. calculate the length of both vectors.
b. find a unit vector C, that points the same direction as A.
c. calculate the length of C to verify that it is unity.
d. find the angle between the two vectors A and B.
e. find the vector D that points from B to A.
f. find the vector E that points from A to B.