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If `l ,m ,n`are the three positive roots of the equation `x^3-a x^2+b x-48=0,`then the minimum value of `(1//l)+(2//m)+(3//n)`equals`1``2``3//2``5//2`A. 1B. 2C. `3//2`D. `5//2` |
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Answer» Correct Answer - C Consider 1/l, 2/m, 3/n and use A.M `ge` G.M. Then `:. (1)/(3) ((1)/(l) + (2)/(m) + (2)/(n)) ge ((6)/(48))^(1//3) = (1)/(2)` `:. ((1)/(l) + (2)/(m) + (3)/(n))_("min") = (3)/(2)` |
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