Page 197 - Elementary_Linear_Algebra_with_Applications_Anton__9_edition

Draw a picture that shows four nonzero vectors whose sum is zero.
18.

If you were given four nonzero vectors, how would you construct geometrically a fifth vector that
19. is equal to the sum of the first four? Draw a picture to illustrate your method.

Consider a clock with vectors drawn from the center to each hour as shown in the accompanying
20. figure.

(a) What is the sum of the 12 vectors that result if the vector terminating at 12 is doubled in
length and the other vectors are left alone?

(b) What is the sum of the 12 vectors that result if the vectors terminating at 3 and 9 are each
tripled and the others are left alone?

(c) What is the sum of the 9 vectors that remain if the vectors terminating at 5, 11, and 8 are
removed?

Figure Ex-20

Indicate whether the statement is true (T) or false (F). Justify your answer.
21.

(a) If , then .

(b) If , then for all a and b.

(c) Parallel vectors with the same length are equal.

(d) If , then either or .

(e) If , then u and v are parallel vectors.

(f) and are equivalent.
The vectors