Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Vectors

Question:

Find the direction cosines of the vector (5\(\hat{i}\) + \(\hat{j}\)+ 2\(\hat{k}\)) 

Options:

-(5/ √30,  1/√30,  2/√30)

(5/ √30,  1/√30,  2/√30)

(5/ √30,  2/√30,  2/√30)

(5/ √30,  1/√30,  5/√30)

Correct Answer:

(5/ √30,  1/√30,  2/√30)

Explanation:

Let   vectors  \(\vec{a}\)= (5\(\hat{i}\) + \(\hat{j}\)+ 2\(\hat{k}\))     

    magnitude of (\(\vec{a}\)) =√(5)2 +(1)2 +(2)2 = √30

  Hence the direction cosines are  =(5/ √30,  1/√30,  2/√30)