DR’s of L3=m×n=i^1−1j^−12k^21=−5i^−3j^+k^L3:−5x−α=−3y−β=1z−γ=λA(α−5λ,β−3λ,γ+λ)L1:1x−1=−1y−2=2z−1=k B(k+1,−k+2,2k+1) Now $\begin{aligned}
& \alpha-5 \lambda=\mathrm{k}+1 \Rightarrow \alpha=5 \lambda+\mathrm{k}+1 \
& \beta-3 \lambda=-\mathrm{k}+2 \Rightarrow \beta=3 \lambda-\mathrm{k}+2 \
& \gamma+\lambda=2 \mathrm{k}-1 \Rightarrow \gamma=-\lambda+2 \mathrm{k}+1 \
& |5 \alpha-11 \beta-8 \gamma|=|-25| \
& =25
\end{aligned}$
Let L_1: x-1 1= y-2 -1= z-1 2 and L_2: x+1 -1= y-2 2= z 1 be two lines. Let L_3 be a line passing through the point (α, β, γ) and be perpendicular to…
JEE Main 2025 — Mathematics Vectors & 3D Geometry
Let L1:1x−1=−1y−2=2z−1 and L2:−1x+1=2y−2=1z be two lines. Let L3 be a line passing through the point (α,β,γ) and be perpendicular to both L1 and L2. If L3 intersects L1, then ∣5α−11β−8γ∣ equals :
Held on 29 Jan 2025 · Verified 6 Jul 2026.
Options
- A
20
- B
18
- C
25
- D
16
Did you get this right?
Sign in to track your attempts and accuracy.
Your note
Sign in to keep a private note on this question. Nothing you write is ever public.
JEE Main Vectors & 3D Geometry in other years
More JEE Main Vectors & 3D Geometry questions
Let $\hat{u}$ and $\hat{v}$ be unit vectors inclined at an acute angle such that $|\hat{u}\times\hat{v}|=\dfrac{\sqrt{3}}{2}$. If $\vec{A}=\lambda\hat{u}+\hat{v}+(\hat{u}\times\hat{v})$, then $\lambda$ is equal to:
Let $\vec{a}, \vec{b}, \vec{c}$ be three vectors such that $\vec{a} \times \vec{b}=2(\vec{a} \times \vec{c})$. If $|\vec{a}|=1,|\vec{b}|=4,|\vec{c}|=2$, and the angle between $\vec{b}$ and $\vec{c}$ is $60^{\circ}$, then $|\vec{a} \cdot \vec{c}|$ is equal to
If the distances of the point $(1,2, a)$ from the line $\frac{x-1}{1}=\frac{y}{2}=\frac{z-1}{1}$ along the lines $\mathrm{L}_{1}: \frac{x-1}{3}=\frac{y-2}{4}=\frac{z-a}{b}$ and $\mathrm{L}_{2}: \frac{x-1}{1}=\frac{y-2}{4}=\frac{z-a}{c}$ are equal, then $a+b+c$ is equal to
If the distance of the point $\mathrm{P}(43, \alpha, \beta), \beta<0$, from the line $\overrightarrow{\mathrm{r}}=4 \hat{i}-\hat{k}+\mu(2 \hat{i}+3 \hat{k}), \mu \in \mathbf{R}$ along a line with direction ratios $3,-1,0$ is $13 \sqrt{10}$, then $\alpha^{2}+\beta^{2}$ is equal to $\_\_\_\_$
Let $\overrightarrow{\mathrm{AB}}=2 \hat{i}+4 \hat{j}-5 \hat{k}$ and $\overrightarrow{\mathrm{AD}}=\hat{i}+2 \hat{j}+\lambda \hat{k}, \lambda \in \mathbb{R}$. Let the projection of the vector $\vec{v}=\hat{i}+\hat{j}+\hat{k}$ on the diagonal $\overrightarrow{\mathrm{AC}}$ of the parallelogram ABCD be of length one unit. If $\alpha, \beta$, where $\alpha>\beta$, be the roots of the equation $\lambda^{2} x^{2}-6 \lambda x+5=0$, then $2 \alpha-\beta$ is equal to
Other Mathematics topics for JEE Main
Keep practicing Vectors & 3D Geometry
Work through every JEE Main Vectors & 3D Geometry PYQ, year by year.