Extremely Simplistic Proof Check

  • Thread starter Thread starter Hotsuma
  • Start date Start date
  • Tags Tags
    Proof
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
5 replies · 1K views
Hotsuma
Messages
41
Reaction score
0
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
 
Physics news on Phys.org
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.
 
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.