CBSE Class 11-science Answered

Asked by Topperlearning User | 30 Sep, 2016, 06:03: PM

Expert Answer

$A space G. P space w i t h space f i r s t space t e r m space a space a n d space c o m m o n space r a t i o space r space i s space g i v e n space b y space a comma a r comma a r squared comma.... W e space n e e d space t o space f i n d space S subscript n equals space a plus a r plus a r squared plus... plus a r space to the power of n minus 1 end exponent space S subscript n left parenthesis a minus a r right parenthesis equals left parenthesis a minus a r right parenthesis left parenthesis a plus a r plus a r squared plus... plus a r space to the power of n minus 1 end exponent right parenthesis space space space space space space space space space space space space space space space space space space space space equals left parenthesis a squared plus a squared r plus a squared r squared plus... plus a squared r to the power of n minus 1 end exponent right parenthesis minus left parenthesis a squared r plus a squared r squared plus... plus a squared r to the power of n right parenthesis space space space space space space space space space space space space space space space space space space space space space equals a squared minus a squared r to the power of n S subscript n equals fraction numerator a left parenthesis 1 minus r to the power of n right parenthesis over denominator 1 minus r end fraction f o r space vertical line r vertical line less than 1 space a n d space n rightwards arrow infinity space r to the power of n rightwards arrow 0 s o space S subscript infinity equals a divided by left parenthesis 1 minus r right parenthesis$

Answered by | 30 Sep, 2016, 08:03: PM

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CBSE Class 11-science Answered

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