$\cos\theta = \frac{\vec{a} \cdot \vec{b}}{|\vec{a}||\vec{b}|} = \frac{1}{\sqrt{2} \cdot \sqrt{2}} = \frac{1}{2}$
$$\theta = \frac{\pi}{3}$$
Back to JEE Main 2021 Vectors & 3D Geometry
JEE Main 2021 — Mathematics Vectors & 3D Geometry
easy
mcq
2021
Official previous-year question
Verified 30 May 2026.
Question
The angle between vectors $\vec{a} = \hat{i} + \hat{j}$ and $\vec{b} = \hat{j} + \hat{k}$ is:
Options
- A
$\frac{\pi}{3}$
- B
$\frac{\pi}{2}$
- C
$\frac{\pi}{4}$
- D
$\frac{\pi}{6}$
Solution
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