JEE Main 2024 · MathsNumerical answerNumerical valueEasyApplication

JEE Main 27 January 2024, Shift 1, Maths Q28

Question 28 of 90 in this shift, Maths question 28 of 30, Section B.

The least positive integral value of

\alpha

, for which the angle between the vectors

\alpha\hat{i}-2\hat{j}+2\hat{k}

and

\alpha\hat{i}+2\alpha\hat{j}-2\hat{k}

is acute, is ________.

Official answer

NTA final key.

Chapter: Vector Algebra
Topic: Dot Product
Idea tested: Acute and Obtuse Angle Conditions

Same idea in other shifts

Asked 3× in all

8 Apr 2024, Shift 1 · Q18The set of all $\alpha$ , for which the vectors $\vec{a}=\alpha t\hat{i}+6\hat{j}-3\hat{k}$ and…MediumSingle correct
28 Jul 2022, Shift 2 · Q77Let S be the set of all $a\in\mathbb{R}$ for which the angle between the vectors $\vec{u}=a(\log_e b)\hat{i}-6\hat{j}+3\hat{k}$ and…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.