1.

If A, B, C be an acute angled triangle, then the minimum value of `tan^(4)A+tan^(4)B+tan^(4)C` will beA. 729B. 27C. `81sqrt3`D. none of these

Answer» Correct Answer - B
In a triangle ABC, we know that
`tanA+tanB+tanCge3sqrt3" "...(i)`
We also know that
`(tan^(4)A+tan^(4)B+tan^(4)C)/(3)ge((tanA+tanB+tanC)/(3))^(4)`
`implies(tan^(4)A+tan^(4)B+tan^(4)C)/(3)ge(sqrt3)^(4)" "["Using(i)"]`
`impliestan^(4)A+tan^(4)B+tan^(4)C ge27`


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