Problem Compute the value of b if A and B are orthogonal. $${\bf A} = 2{\bf i} + b{\bf j} + {\bf k}$$

$${\bf B} = 4{\bf i} - 2{\bf j} - 2{\bf k}$$

Answer Key

Solution

$2(4) + b(-2) + 1(-2) = 0$

$2b = 6$

$b = 3$ ← Answer: [ D ]

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