If a line makes angles 60°, 135°

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Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Three-dimensional Geometry

Question:

If a line makes angles 60°, 135°, and 45° with X, Y and Z-axes respectively, then it's direction cosines will be-

Options:

1/2, 1/√2, 1/√3

1/2, -1/√2,- 1/√2

1/2, -1/√2, 1/√2

-1/2, -1/√2, 1/√2

Correct Answer:

1/2, -1/√2, 1/√2

Explanation:

Let the direction cosines of the lines be l, m, n. Then l= cos(60°)=1/2 , m= cos(135°)= -1/√2, n = cos(45°) = 1/√2