Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Vectors

Question:

If $\theta \in [0, \pi ]$ is the angle between any two non zero vectors $\vec{a}$ and $\vec{b}$, such that $|\vec{a}.\vec{b}|=|\vec{a}×\vec{b}|$ then $\theta = $

Options:

$\frac{\pi}{2}$

$\frac{\pi}{4}$

0

$\pi $

Correct Answer:

$\frac{\pi}{4}$

Explanation:

The correct answer is Option (2) → $\frac{\pi}{4}$

$|\vec{a}.\vec{b}|=|\vec{a}×\vec{b}|$

$=|\vec{a}||\vec{b}|\cos θ=|\vec{a}||\vec{b}|\sin θ$

$\cos θ=\sin θ⇒θ=\frac{\pi}{4}$