Question

Q24. a) Determine the value of n, so that vectors A = 2ỉ +4j-nk and B = 3i - 4; +2k
are perpendicular.
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Answer 1

Two vectors vector A = 2i - 3j + k and vector B = 3i + 4j + nk will be perpendicular to each other if vector(A.B) = 0 or, (2i - 3j + k)(3i + 4j + nk) = 0 or, 6(i.i) - 12(j.j) + n(k.k) = 0 or, 6 - 12 + n = 0 or, n = 6 [∵ i.i = j.j = k.k = 1]

Hope that helps !!