) P be any point on line L. P(1+2λ,2−3λ,−2−6λ) and A(1,2,−2) Given, AP=21 √(2λ)2+(−3λ)2+(−6λ)2=21 ⇒|λ|(√4+9+36)=21 ⇒|λ|=3⇒λ=±3 At λ=3,P(7,−7,−20) Position vector of P:7
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i
−7
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j
−20
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k
At λ=−3 and P(−5,11,16) Position vector of P:−5