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Find the sum of the sequence 5, 55, 555... to n terms . |
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Answer» 5(1,11,111+...+ n)5/9(9+99+999+...+n)5/9(10-1+100-1+1000-1+...+n)5/9(10+100+1000+...+(-1)^n)because 10 +100+1000 are in GP so,we are using the formula of sum of GP.5/9{10(10^n-1/9)+(-1)^n} 5/81(10×(10^n-1)-9n) |
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