Question

The angle between two vectors $(2\widehat{i} + 3\widehat{j} + \widehat{k})$ and $(–3\widehat{i} + 6\widehat{k})$ is-

• A. (a) $0^{0}$
• A. (b) $45^{0}$
• A. (c) $60^{0}$
• A. (d) $90^{0}$

Answer 1

(d)

cosq =$\frac{\overset{\rightarrow}{P}.\overset{\rightarrow}{Q}}{PQ}$=$\frac{–6 + 0 + 6}{\sqrt{2^{2} + 3^{2} + 1^{2}}\sqrt{(–3)^{2} + 6^{2}}}$=0

$\theta = 90^{0}$