Question :A= 3î− ĵ+ 7k̂ and B = 5î− ĵ+ 9k̂ the direction cosine m of the vector A+ B is
(A) zero
(B) \dfrac{3}{\sqrt{31}}
(C) \dfrac{9}{\sqrt{107}}
(D) 5
Answer : option (A)
Solution :
A= 3î− ĵ+ 7k̂ and B = 5î− ĵ+ 9k̂ the direction cosine m of the vector A⃗ + B is
with
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