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# This belongs to Dc's and dr's if the dc's of two lines are connected by relations l +m-n =0 6ln -12lm+ mn =0 then dc's of two line are.....? (1/root14,2/root14,3/root14) , (1/root26,3/root26,4/root26)

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## The answer is option A (1/root14,2/root14,3/root14) Given below is the steps to solve this problem. At first consider the fact that there are 3 unknowns and only 2 equations are given. But we know the general property of direction cosines. They are governed by the equation; l²+m²+n²=1 Now we have 3 equations and 3 unknowns. Now write l in terms of m and n, this will reduce the number of variables to two. Substitute this in second equation. Now you will get 2 equation and 2 unknowns. Substitute this in third equation to get the final third degree equation. Solving this will give the above mentioned result. Thank you  Suggest Corrections  0      Similar questions
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