Mathbee CBSE Mathbee · CBSE Class 12 Maths
CBSE Class 12 Mathematics 2026 Main Paper 65/2/2 · Q191 Marksdirection_cosines

CBSE Class 12 Mathematics 2026 Main Paper 65/2/2 · Question 19 (Three Dimensional Geometry)

Assertion: A line can have direction cosines (1,1,1). Reason: cos θ=1 is possible for θ=0.

✅ Step-by-Step Solution

Final Answer: The assertion is false and the reason is true.
  1. The squares of a line’s direction cosines must sum to one, but here they sum to three. The stated cosine value is true.

Master Chapter 11: Three Dimensional Geometry

Practise interactive questions, flashcards, visual mind maps, and timed board tests for Three Dimensional Geometry.
📘 Chapter Notes & All Exercises 🚀 Open Interactive Workspace →
← Previous Question
If \(e^{x+y}=3x\), find dy/dx.
Next Question →
Assertion: |a×b|²+(a·b)²=|a|²|b|². Reason: |a×b|=(a·b) tan θ for…

All Questions in CBSE Class 12 Mathematics 2026 Main Paper 65/2/2

Q1Q2Q3Q4Q5Q6Q7Q8Q9Q10Q11Q12Q13Q14Q15Q16Q17Q18Q19Q20Q21Q22Q23Q24Q25Q26Q27Q28Q29Q30Q31Q32Q33Q34Q35Q36Q37Q38

Related Questions in Three Dimensional Geometry

Class 12 Three Dimensional Geometry · Mcq Single Correct
Find the foot of the perpendicular from (2,−3,4) to the y-axis.
Class 12 Three Dimensional Geometry · Mcq Single Correct
A line makes angles α,β,γ with the positive coordinate axes. Find cos 2α+cos 2β+cos 2γ.
Class 12 Three Dimensional Geometry · Mcq Single Correct
Find the distance of (α,β,γ) from the y-axis.
Class 12 Three Dimensional Geometry · Mcq Single Correct
Find direction cosines of (x−1)/2=(1−y)/3=(2z−1)/12.
Class 12 Three Dimensional Geometry · Mcq Single Correct
Find the acute angle between two distinct body diagonals of a cube.
Class 12 Three Dimensional Geometry · Mcq Single Correct
A line makes angles θ₁,θ₂,θ₃,θ₄ with the four body diagonals of a cube. Find Σ cos²θᵢ.