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A triangle `A B C` is inscribed in a circle with centre at `O ,` The lines `A O ,B Oa n dC O` meet the opposite sides at `D , E ,a n dF ,` respectively. Prove that `1/(A D)+1/(B E)+1/(C F)=(acosA+bcosB+ccosC)/`

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ARIHANT MATHS-PROPERTIES AND SOLUTION OF TRIANGLES -Exercise (Single Integer Answer Type Questions)
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  9. In a DeltaABC, the maximum value of 120((sum a cos ^(2)((A)/(2)))/(a+...

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  12. If a, b and A are given in a triangle and c(1), c(2) are possible valu...

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  14. A triangle A B C is inscribed in a circle with centre at O , The lines...

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  15. In Delta ABC, a ge b ge c and if (a^(3) +b^(2)+ c^(2))/(sin ^(3) A sin...

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  16. In a cyclic quadrilateral PQRS, PQ= 2 units, QR= 5 units, RS=3 units ...

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