Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Three-dimensional Geometry

Question:

Consider the equation of the line $\vec r= -\hat i + 2\hat k + μ(4\hat i −\hat j + 2\hat k),$

Match List-I with List-II

List-I

List-II

(A) It passes through the point

(I) $4, -1, 2$

(B) Its direction ratios are

(II) $\frac{4}{\sqrt{21}},\frac{-1}{\sqrt{21}},\frac{2}{\sqrt{21}}$

(C) Its Cartesian form is

(III) $(-1, 0, 2)$

(D) Its direction cosines are

(IV) $\frac{x+1}{4}=\frac{y}{-1}=\frac{z-2}{2}$

Choose the correct answer from the options given below:

Options:

(A)-(I), (B)-(III), (C)-(IV), (D)-(II)

(A)-(III), (B)-(II), (C)-(IV), (D)-(I)

(A)-(I), (B)-(II), (C)-(IV), (D)-(III)

(A)-(III), (B)-(I), (C)-(IV), (D)-(II)

Correct Answer:

(A)-(III), (B)-(I), (C)-(IV), (D)-(II)

Explanation:

The correct answer is Option (4) → (A)-(III), (B)-(I), (C)-(IV), (D)-(II)

List-I

List-II

(A) It passes through the point

(III) $(-1, 0, 2)$

(B) Its direction ratios are

(I) $4, -1, 2$

(C) Its Cartesian form is

(IV) $\frac{x+1}{4}=\frac{y}{-1}=\frac{z-2}{2}$

(D) Its direction cosines are

(II) $\frac{4}{\sqrt{21}},\frac{-1}{\sqrt{21}},\frac{2}{\sqrt{21}}$

Given line: $\vec{r} = -\hat{i} + 2\hat{k} + \mu(4\hat{i} - \hat{j} + 2\hat{k})$

Compare with: $\vec{r} = \vec{a} + \mu \vec{b}$

  • Point on the line (position vector) = $(-1, 0, 2)$
  • Direction ratios = $(4, -1, 2)$
  • Direction cosines = $\left( \frac{4}{\sqrt{21}}, \frac{-1}{\sqrt{21}}, \frac{2}{\sqrt{21}} \right)$
  • Cartesian form: $\displaystyle \frac{x+1}{4} = \frac{y}{-1} = \frac{z-2}{2}$