Proving Induction: n4 <= 4n + 17 | Math Algebra Homework

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Homework Help Overview

The discussion revolves around proving an inequality involving induction, specifically the statement that for all natural numbers n, \( n^4 \leq 4n + 17 \). Participants are exploring the steps necessary to establish this inequality through mathematical induction.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants are attempting to clarify the induction process and the specific algebraic manipulations required to prove the inequality. There are questions about the validity of the base case and the assumptions made in the induction step.

Discussion Status

Some participants are questioning the initial conditions and the correctness of the expressions used in the proof. There is a recognition of the need for clarity in the problem statement and the steps taken so far, with suggestions for providing a complete context to facilitate better assistance.

Contextual Notes

There are indications of confusion regarding the formulation of the problem, particularly concerning the inequality signs and the expressions involved. Participants are encouraged to provide complete details of their attempts to aid in the discussion.

lovemake1
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Homework Statement

The induction question is. for all natural n, n4 <= 4n + 17Base case: 0 Works, since 0 < 1 + 17 then,
I assume that for all n in natural, n4 <= 4n + 17 holds.Now I believe I need to show that, 4(n4) <= 4(4n + 17)
that is, 4n+1 + 17 >= (n+1)4
To do so, I prove, 4n4 >= (n+1)4,
which proves that 4n+1 + 17 >= (n+1)4How would I prove.. 4n4 >= (n+1)4 = n4 + 4n3 + 6n2 + 4n + 1

This step is in the middle of my induction proof and it is neccesary part of my induction step.

How would I go about doing this?
Some easier version similar to this deals with power of 2 or n, which seems rather simple. but, this one I am having hard time.
Help is much appreciated.

Homework Equations


The Attempt at a Solution



I tried starting from n4 = n4 and start adding things to both sides but the onlything I can add to left is n4 so I am not entirely sure how to go about doing this type of math. please some tricks and help is appreciated.
 
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lovemake1 said:

Homework Statement



I am working on an induction problem but somehow I need to prove.
using algebra and such. 4n4 > (n+1)4 = n4 + 4n3 + 6n2 + 4n + 1

This step is in the middle of my induction proof and it is necessary part of my induction step.

How would I go about doing this?

Homework Equations



The Attempt at a Solution



I tried starting from n4 = n4 and start adding things to both sides but the only thing I can add to left is n4 so I am not entirely sure how to go about doing this type of math. please some tricks and help is appreciated.
Please state the whole problem as it was given to you.

You're more likely to get help that way.

Also, at least sketch out your solution up to the point you're having trouble. It's hard for us to guess what you're trying to accomplish otherwise.
 
Agreed, for example this expression certainly isn't true for n=1, so for the induction to take place, where are you starting from?
 
oay said:
Agreed, for example this expression certainly isn't true for n=1, so for the induction to take place, where are you starting from?


I added the full question with my understandings.
 
oay said:
Agreed, for example this expression certainly isn't true for n=1, so for the induction to take place, where are you starting from?

sorry I fixed the problem. it's >= instead of >
thanks,
 
lovemake1 said:
I added the full question with my understandings.

But you've changed the whole question since you last asked it. It is now a mess. Unless you yet again change it.

And n4+1 is not the same as 4n4 which is how you have it written here, before you change it again!
 

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