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यदि ` S _ n = 1 + q + q ^ 2 + .... + q ^n ` ` S _ n = 1 + ( q + 1 ) / ( 2 ) + ( (q + 1 ) /( 2 ))^ 2 + ... + ( ( q + 1 )/( 2 ))^n , q ne 1 ` तब सिद्ध कीजिए कि - ` ""^ ( n + 1 ) C _ 1 + ""^ (n + 1 ) C _ 2 S _ 1 + ""^ (n + 1 ) C _ 3 S _ 2 + ... + ""^ (n + 1 ) C _ ( n + 1 ) S _ (n ) = 2^n S _ n ` |
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Answer» स्पष्टतः ` S _ n = ( 1 - q ^ ( n + 1 ) )/( 1 - q ) " "`...(i) तथा ` S_ n = (1 - ( ( q + 1 ) /( 2 )) ^ ( n + 1 ) ) /( 1 - (q + 1 ) / ( 2 ) ) = ( 2 ^ (n + 1 ) - ( q + 1 ) ^ ( n + 1 ) ) /( 2 ^n ( 1 - q )) " "`...(ii) इसलिए ` ""^ ( n + 1 ) C _ 1 + ""^ ( n +1 ) C _ 2 * S _ 1 + ""^ (n + 1 ) C _ 3 S _ 2 + ... + ""^ ( n + 1 ) C _ (n + 1 ) S _ n ` ` = ( 1 ) /( 1 - q ) [""^ ( n + 1 ) C _ 1 ( 1 - q ) + ""^ ( n + 1 ) C _ 2 ( 1 - q ^2 ) + ""^ ( n +1) C _ 3 ( 1 - q ^ 3 ) + ... + ""^ ( n + 1 ) C _ (n + 1 ) ( 1 - q^( n + 1 )] ` ` = ( 1 ) / ( 1 - q ) [ ""^ (n + 1 ) C _ 1 + ""^ ( n + 1 ) C _ 2 + ... + ""^ (n + 1 ) C _ ( n + 1 ) ] - [ ""^ ( n + 1 ) C _ 1 * q + ""^ ( n + 1 ) C _ 2 * q ^ 2 + ... + ""^ ( n + 1 ) C _ ( n + 1 ) * q^ ( n + 1 ) ] ` ` = ( 1 ) /( 1- q ) [ ( 2 ^ ( n + 1 ) - 1 ) - { ( 1 + q ) ^ ( n + 1 ) - 1 } ] = ( 2 ^ ( n + 1) - ( 1 + q ) ^ (n + 1 ) ) / ( ( 1 _ q )) ` ` = 2 ^ n S _ n " " ` (समीकरण (ii ) से ) |
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