JEE Main 2021 · MathsMultiple choiceSingle correctMediumCalculation

JEE Main 26 February 2021, Shift 1, Maths Q62

Question 62 of 90 in this shift, Maths question 2 of 30, Section A.

(1, 5, 35)

(7, 5, 5)

(1, \lambda, 7)

and

(2\lambda, 1, 2)

are coplanar, then the sum of all possible values of

\lambda

is :

(1) $\frac{39}{5}$
(2) $-\frac{39}{5}$
(3) $-\frac{44}{5}$
(4) $\frac{44}{5}$ Official answer

Official answer

Option 4

NTA final key.

Chapter: Three Dimensional Geometry
Topic: Triple Products
Idea tested: Coplanarity of Four Points

Same idea in other shifts

Asked 5× in all

6 Apr 2023, Shift 1 · Q15Let the position vectors of the points A, B, C and D be $5\hat i+5\hat j+2\lambda\hat k$ , $\hat i+2\hat j+3\hat k$ ,…MediumSingle correct
6 Apr 2023, Shift 2 · Q17The sum of all values of $\alpha$ , for which the points whose position vectors are $\hat{i}-2\hat{j}+3\hat{k}$ ,…MediumSingle correct
11 Apr 2023, Shift 2 · Q17If four distinct points with position vectors $\vec{a}, \vec{b}, \vec{c}$ and $\vec{d}$ are coplanar, then $[\vec{a}\ \vec{b}\ \vec{c}]$ …MediumSingle correct
29 Jul 2022, Shift 2 · Q15If $(2, 3, 9)$ , $(5, 2, 1)$ , $(1, \lambda, 8)$ and $(\lambda, 2, 3)$ are coplanar, then the product of all possible values of $\lambda$ is :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.