Prove that (n-1, r)+(n, r-1)=(n,r) ​

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Prove that (n-1, r)+(n, r-1)=(n,r)

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Phúc Điền 3 months 2021-08-15T08:14:51+00:00 1 Answers 1 views 0

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    2021-08-15T08:16:35+00:00

    Answer:

     \binom{n - 1}{r}  +  \binom{n}{r - 1}  =  \binom{n}{r}  \\( n - 1) + n = n \\ n - 1 = 0 \\ n = 1 \\ r + (r - 1) = r \\ r = 1 \\  \binom{0}{1}  +  \binom{1}{0}  =  \binom{1}{1}

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