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

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SUMMARY

The discussion centers on proving the inequality n4 ≤ 4n + 17 for all natural numbers n using mathematical induction. The user initially establishes the base case and assumes the statement holds for n, then seeks to prove it for n + 1 by demonstrating that 4n4 ≥ (n + 1)4. The conversation highlights the importance of correctly formulating the induction hypothesis and addressing potential errors in the initial assumptions, particularly regarding the inequality's validity for n = 1.

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  • Understanding of mathematical induction
  • Familiarity with polynomial expressions and their expansions
  • Knowledge of algebraic manipulation techniques
  • Ability to analyze inequalities
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  • Study the principles of mathematical induction in detail
  • Learn how to expand binomial expressions, specifically (n + 1)4
  • Explore techniques for proving inequalities involving polynomials
  • Practice similar induction problems to reinforce understanding
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Students studying algebra, particularly those tackling mathematical induction proofs, as well as educators looking for examples of common pitfalls in induction problems.

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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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