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Vector Algebra

Question
CBSEENMA12035869

Write the value of p for which a = 3i^ + 2j^ + 9k^   and    b = i^+pj^ +3k^ are parallel vectors.

Solution

Two vectors a  and  b are parallel

a = 3i^ + 2j^ + 9k^   and   b = i^ + pj^ + 3k^ a =λ bSo  3i^ + 2j^ + 9k^  = λ  i^ + pj^ + 3k^ 3i^ + 2j^ + 9k^  =λ i^ + p λ j^ + 3 λ k^ λ = 3,   p λ = 2   and  9 = 3 λ p = 23