MHT CET202019 Oct 2020Morning ShiftMathematicsVector AlgebraActual

The direction ratios of the line perpendicular to the lines having direction ratios 2,3,1 and 1,2,1 are

Options

A-2,1,1
B1,1,1
C1,-1,1
D2,2,-2

Correct answer

C. 1,-1,1

Step-by-step solution

(D) Let a and b be the vectors along the lines whose direction ratios are 2,3,1 and 1,2,1 respectively. a =2 i +3 j + k and b = i +2 j + k A vector perpendicular to both a and b is given by, a b = | array ccc i & j & k 2 & 3 & 1 1 & 2 & 1 array |= i (3-2)- j (2-1)+ k (4-3)= i - j + k Hence d.r.s are 1,-1,1

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