Homework 1

This assignment is due by the beginning of class on Wednesday, September 3rd. Be sure to review the homework guidelines before getting started.

  • Prove that for any n \in \mathbb{Z} and any positive integer k, at least one number from the set \{n,n+1,\cdots, n+k-1\} is divisible by k. (Note: I made a small change to the problem since the original posting. The old version can also be solved, but this is a little more precise, so it's a better result to carry around in your toolbox.)
  • From Strayer, do the following problems:
    • 5
    • 10(a)
    • 11(b),(d)
    • 18
    • 21(b),(d)
    • 23
    • 29

It would also be good to get some practice on other problems, even though I won't be collecting them. For this, I'd suggest you take a look at the following problems from Strayer: 1(c), 1(d), 2, 3(b), 12, 25, 30. Any other problems you want to work on are also good practice, so if these problems all seem to easy, try out some others on your own.

Homework 1
Liebers87Liebers87 1220137504|%e %b %Y, %H:%M %Z|agohover

Heyy! Having some trouble with proving the first part. I broke it down into three different cases and proved that it held true for all the cases. My cases were as follows:

1) n > k
2) n < k
3) n = k

Anyone else go about this problem differently??

Also, on the homework, I thought it was very helpful on problem 11 to prove that any even plus any odd is equal to an odd number. After proving that, I used that claim to prove the other parts.

Well anyway, if you could provide any input on the first problem, that would be very helpful. Thanks!

~Alex

unfold Homework 1 by Liebers87Liebers87, 1220137504|%e %b %Y, %H:%M %Z|agohover
Re: Homework 1
jensbergjensberg 1220203092|%e %b %Y, %H:%M %Z|agohover

Try using the division algorithm on n, with d=k. Then you just need to figure out how to show that for each possible r, you can find an element in the set that would be divisible by k.

unfold Re: Homework 1 by jensbergjensberg, 1220203092|%e %b %Y, %H:%M %Z|agohover
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