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` ( 1 + x ) ^n ` के विस्तार में , यदि ` P(n)` द्विपद गुणांकों का गुणनफल है, तब सिद्ध कीजिए कि - ` (P ( n + 1 )) /( P (n ) ) = ((n + 1 )^n )/ ( n!) ` |
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Answer» बायाँ पक्ष = ` (""^ ( n + 1 ) C_ 0 * ""^ (n + 1 ) C _ 1 * ""^ ( n + 1 ) C _ 2 ... ""^ ( n + 1 ) C _ r .... ""^ ( n + 1 ) C _ ( n + 1 ))/( ""^ nC _ 0 * ""^n C _ 1 *""^nC _ 2 ... ""^ n C _ r ... ""^n C _ n ) ` ` ""^ ( n + 1 ) C _ 0 = ""^ n C _ 0 = 1 ` तथा ` ""^ ( n + 1 ) C _ ( n + 1 ) = 1 ` रखने पर , ` therefore ( P ( n + 1 ))/( P (n )) = (""^ ( n + 1 ) C _ 1 ) /( ""^ n C _ 1 ) * (""^ (n + 1 ) C _ 2 ) /( ""^ n C _ 2) ... ( ""^ ( n + 1 ) C _ r ) / ( ""^ n C _ r ) ... ( ""^ ( n + 1 ) C _ n ) /( ""^nC _ n ) ` इसलिए ` (""^ (n + 1 ) C _ r) /( ""^ n C _ r ) = (( n + 1 ) ! )/( r! ( n - r + 1 ) ! ) * (r ! ( n- r ) ! ) /( n ! ) = ((n + 1))/( (n - r + 1 )) " " ( 1le r le n ) ` ` r = 1, 2, 3,..., n ` रखकर प्रत्येक की गुणा करने पर, ` (P ( n + 1))/( P ( n )) = ((n + 1 ) ( n + 1 ))/( n ( n - 1 ) ...2 * 1 ) = (( n + 1 ) ^n ) /( n! ) ` |
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