Find vectors a.b when i. vector a = i - 2j + k and vector b = 3i - 4j - 2k

Question

Find vectors a.b when

(i) vectors a = i - 2j + k and vectors b = 3i - 4j - 2k

(ii) vectors a = i + 2j + 3k  and vectors b = -2j + 4 k

(iii) vectors a = i - j + 5k  and vectors b = -3i - 2k

Answer 1

(i) \(\vec{a} =\vec {i}-\vec{2j}+\vec{k} \)

\(\vec{b} =\vec {3i}-\vec{4j}-\vec{2k} \)

(ii)  \(\vec{a} =\vec {i}+\vec{2j}+\vec{3k} \)

\(\vec{b} =\vec {0i}-\vec{2j}+\vec{4k} \)

 (iii)  \(\vec{a} =\vec {i}-\vec{j}+\vec{5k} \)

 \(\vec{b} =\vec {3i}+\vec{0j}-\vec{2k} \)