hi can you tell
is xi is the set of all the divisors of n ?
If x1,x2,x3,....,xk are the divisors of positive integer n. If Σxi=75 then find Σ(1/xi)?
[7]
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10 Answers
Abhishek Priyam
·2009-01-07 06:11:02
its the lang given in the question.. :(
But i think it should be all divisors...
I solved it in 11th but when tried it now for revision i am clueless :(
Hari Shankar
·2009-01-07 07:53:34
Let S = x1+x2+...+xn
Remember that if d is a divisor, then so is n/d.
2S = Σ1/xi+Σxi/n = S + 75/n
Hence S = 75/n
Abhishek Priyam
·2009-01-07 08:06:51
[1]
Yes i got same answer and sorry 4 not replying as there was a power cut..
Philip Calvert
·2009-01-07 08:08:56
how
2S = Σ1/xi+Σxi/n = S + 75/n [7]
sorry if its stupid but got a mental block presently [2]
Abhishek Priyam
·2009-01-07 08:12:04
x1.y1=n
x2.y2=n
..
.
so Σ1/xi=Σyi/n
yi are also the divisors hence the answer..
Hope its clear..