Extremely Simplistic Proof Check

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Homework Help Overview

The discussion revolves around proving the inequality n^3 > n^2, which is part of a computer math class assignment. Participants are exploring the validity of a simplistic proof approach and the assumptions involved.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to simplify the proof by manipulating the inequality directly. Some participants question the assumptions made in the proof and suggest alternative approaches, including induction. Others emphasize the importance of clarifying the nature of the variable n.

Discussion Status

The discussion is active, with participants providing feedback on the original proof attempt and suggesting that the proof may be simpler than initially thought. There is a recognition of the need to clarify assumptions about n, particularly regarding its value.

Contextual Notes

There is an implicit assumption that n is a natural number greater than 1 for the inequality to hold true. Participants are also considering whether induction is necessary for the proof.

Hotsuma
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Doing this simplistic proof for one of my computer math classes. I've already taken Abstract Algebra and I'm having trouble with this lol. Actually, I just need someone to verify this is correct for me. It seems far too simple.

Homework Statement



Prove the following [tex]n^3 > n^2[/tex].

Homework Equations



None of importance...

The Attempt at a Solution



Well, I really just think it is something as simple as:

[tex]\frac{n^3}{n^2}>\frac{n^2}{n^2} \Rightarrow n > 1[/tex]

...unless I'm really missing something
 
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could be wrong i think you might have used the original theorem

as
[tex]\frac{1}{n^2} = \frac{1}{n^2}[/tex]
then you effectively multiply the expression by
[tex]n^2 > n^3[/tex]

however it only a slight tweak to change the proof, start with the assumption:
1<n
then assuming you could use the following property:
if a<b and c>0, then a.c < b.c

otherwise this could be done by induction no worries
 
Oh right, lol, I started with the wrong assumption! Yeah, so, is it really that simple? He he, awesome.
 
if you can assume the property

i think induction would only need to assume 1<n
 
It would be convenient to explain what kind of number n is. A natural number greater than 1?
 
Induction is possible but not needed: if [tex]n > 1[/tex] (which it must be for the desired inequality to be true)
simply look at

[tex] n^3 - n^2[/tex]

think how you show this difference is > 0.
 

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