Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Three-dimensional Geometry

Question:

If the lines $\frac{x-4}{1}=\frac{y-2}{1}=\frac{z-λ}{3}$ and $\frac{x}{1}=\frac{y+2}{2}=\frac{z}{4}$ intersect each other, then λ lies in the interval

Options:

(9, 11)

(-5, -3)

(13, 15)

(11, 13)

Correct Answer:

(11, 13)

Explanation:

Given lines will intersect, if

$\begin{vmatrix}4-0 & 2-(-2) & λ-0\\1 & 1 & 3\\1 & 2 & 4\end{vmatrix}=0$

$⇒ 4(4-6) -4(4-3) + λ(2-1)= 0 $

$⇒ λ = 12 ⇒ λ \,\, ∈ (11, 13)$