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Prove that ∑r-0n3r nCr=4n

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प्रश्न

Prove that `sum_(r-0)^n 3^r  ""^nC_r = 4^n`

योग
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उत्तर

`sum_(r=0)^n 3^r  ""^nC_r =  3^circ  ^nC_0  + 3^1  ^nC_1  + 3^2  ^nC_2  + ..... + 3^n .  ^nC_n`

= `1 +  ^nC_1. 3 +  ^nC_2.  3^2  + ....  ^nC_n . 3^n`

= `(1 + 3)^n  =  4^n`

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अध्याय 7: Binomial Theorem - EXERCISE 7.1 [पृष्ठ १३३]

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एनसीईआरटी Mathematics [English] Class 11
अध्याय 7 Binomial Theorem
EXERCISE 7.1 | Q 14. | पृष्ठ १३३

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