Solving Summation Problem: Show f(n) is Not an Integer

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Homework Statement



Let f(n) = 1/2 + 1/3 + ... + 1/n
Show that f(n) is not an integer for any positive integer n


The Attempt at a Solution



I think that rearraning/breaking down the statement might be easier than applying a theorem since it seems like a simpler problem. Simply arranging the terms got pretty messy so I think the best method is to try to find an integer C such that C x f(n) is not a integer for any value of n. I tried different ways of computing such an integer C, such as taking C to be (n-1)! or something similar for that the summation will give a bunch of integers plus one term that is not an integer but I failed to find such a value. Hopefully someone can help me out over here. Thanks.
 
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I'm a little rusty on this stuff but couldn't we solve this using induction?
 
The funny thing is f(1)=1/1 and 1 is an integer. But, aside from that, IDK.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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