Question

Let $\overrightarrow a$ and $\overrightarrow b$ be two unit vectors. If the vectors $\overrightarrow c=5\overrightarrow a-4\overrightarrow b$ and $\overrightarrow d = \overrightarrow a+2\overrightarrow b$ perpendicular to each other, then the angle between $\overrightarrow a$ and $\overrightarrow b$ is:

• A. 0
• B. $\frac{π}{3}$
• C. $\frac{π}{4}$
• D. $\frac{π}{6}$

Answer 1

Answer: (B)

$\frac{π}{3}$

Answer 2

The correct option is (B):

$\frac{π}{3}$