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Magical Mathematics[Interesting Approach]> The value of sigma r=1 to 10 r*nCr/nCr-1...

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The value of sigma r=1 to 10 r*nCr/nCr-1

Leo Pixie , 10 Years ago

Grade 9

1 Answers

Arun Kumar

Last Activity: 10 Years ago

Hello Student,

$\\\sum_{r=1}^{10}r{_{r}^{n}\textrm{C} \over _{r-1}^{n}\textrm{C}} \\=\sum_{r=1}^{10}(n-r+1) \\=10(n+1)-55 \\=10n-46 \\=5(2n-9)$

Thanks & Regards
Arun Kumar
Btech, IIT Delhi
Askiitians Faculty

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