InterviewSolution
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The sum of the series `1 +3/4+7/16 +15/64+31/256+....` to infinite is: |
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Answer» `=4sum_(n=1)^oo 2^n/4^n-4sum_(n=1)^oo1/4^n` `4sum_(n=1)^oo 1/2^n-4sum_(n=1)^oo 1/4^n` `4[sum_(n=1)^oo 1/2^n-sum_(n=1)^oo 1/4^n]` `4[(1/2)/(1-1/2)-(1/4)/(1-1/4)]` `4[(1/2)/(1/2)-(1/4)/(3/4)]` `4[1-1/3]=4*2/3=8/3`. |
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