Determine the value of 𝑎 so that 𝑨 = 2𝒊 − 𝑎𝒋 + 𝒌 and 𝑩 = 4𝒊 − 2𝒋 − 2𝒌 are perpendicular.
"A=(2,-a,1)", "B=(4,-2,-2)".
Two vectors are perpendicular iff "A\\cdot B=0".
"A\\cdot B=2\\cdot4 + (-a)\\cdot(-2) + 1\\cdot(-2)=8+4a-2=4a+6".
"4a+6=0", so "a=-\\frac32".
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