The set of all , for which the vectors a= αti+6j-3k and b=ti-2j-2 αtk are inclined at an obtuse angle for all t ∈R, is

Question

Accepted Answer

Correct answer: C. (c) a= i+6j-3kb=ti-2j-2 k soab<0 , ∀t ∈R t^2-12+6 t<0 t^2+6 t-12<0 , ∀t ∈R <0 , andD<036 ^2+48 <012 (3 +4 )<0 -43< <0 also fora=0 ,a b<0 hencea ∈ ( -43 ,0 )

$The set of all α, for which the vectors a = αt i + 6 j - 3 k and b = t i - 2 j - 2 αt k are inclined at an obtuse angle for all t \in R, is$

Solution

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