I am not going to post a proof of this, (I once did on this forum maybe I can find it).
But the result you can use is Sylvester's Coin Problem.
In this case,
(3)(5)-(3)-(5)=15-8=7
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I do not understand the second question.
hey hey,
i'm very new in here!!and i got a prob, actually two :
1. prove that any sum of more than 7 cents can be made up out of 3 cents and 5cents coins.
2.using mathematical induction, prove that for all n>1 the following inequality holds: 1/2squert + 1/3squert + .......+ 1/nsquert <1
I am not going to post a proof of this, (I once did on this forum maybe I can find it).
But the result you can use is Sylvester's Coin Problem.
In this case,
(3)(5)-(3)-(5)=15-8=7
---
I do not understand the second question.
the thing is for my second question is to prove that the sum in the left is less or equal to 1 - 1/n !! but i don't know how !
for the first question, i couldn't see anyway i could solve it with that guy's coins' theory!!
anyways, thanks alot for help ! the hw is due tomorrow!! i'll scratch my head and see if i can solve it by midnight ! otherwise ...
thanks again!!