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Algebra

S1,S2,S3 …......... are the sum of infinite geometric series whose first terms are 1,2,3.......... and whose common ratios ½,1/3,1/4, respectivel,then S12 +S22+...................S102 is equal to –
a> 485,b>495,c>500,d>505

Profile image of Pritam Priyadarshan
11 Years agoGrade
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3 Answers

Profile image of manasa gorthy
11 Years ago
S1= 1/(1-1/2)=2                                                                                                                             S2= 2/(1-1/3)=3   similarly S10=11                                                                                                   S12+S22+...................S102=22+32+..............112=505              
Profile image of Vamsi Krishna Velpuri
11 Years ago
S1= 1/(1-1/2)=2                                                                                                                             S2= 2/(1-1/3)=3   similarly S10=11                                                                                                   S12+S22+...................S102=22+32+..............112
=(∑ n2) -1 where n=1 to 11
=>answer is 505-1=504
Profile image of Vamsi Krishna Velpuri
11 Years ago
sorry it is 506-1=505