Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Three-dimensional Geometry

Question:

If a line has direction ratios 3, -4, 5 then it's direction cosines will be-

Options:

3/√50 , -4 /√50 , 5/√50

3/√50 , 4 /√50 , 5/√50

3/√50 , -4 /√50 , -5/√50

-3/√50 , -4 /√50 , 5/√50

Correct Answer:

3/√50 , -4 /√50 , 5/√50

Explanation:

Direction cosines are-

3/√{(3)2 +(-4)2 + (5)2},  -4/√{(3)2 +(-4)2 + (5)2}, 5 /√{(3)2 +(-4)2 + (5)2}

3/√50 , -4 /√50 , 5/√50