Math Induction: Solving (n^3+5n)=6q

In summary, the conversation discussed a problem where n is a natural number and the equation (n^3 + 5n) = 6q. The attempt at a solution involved expanding and simplifying the equation, resulting in 6q + 3n^2 + 3n + 6. The next step was to prove that 3n^2 + 3n + 6 is a multiple of 6 by factoring out 6 and reducing the problem to proving that n^2 + n + 2 is even.
  • #1
kring_c14
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Homework Statement



n [tex]\epsilon[/tex][tex]N[/tex]=n[tex]\geq0[/tex]
6 divides (n[tex]^{3}[/tex]+5n)

Homework Equations


(n[tex]^{3}[/tex]+5n)=6q


The Attempt at a Solution


by expanding and simplifying and later on substituting 6q in
(n+1)[tex]^{}3[/tex]+5(n+1)

ive arrived at 6q+3n[tex]^{}2[/tex] +3n+6

then.. I am stuck...pls help...lot of thanks!
 
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  • #2
i tried multiplying and dividing it by two so that the 6 would be factored out...ive got fractions..its supposed to be whole numbers
 
  • #3
(n+1)^3 +5(n+1)
n^3 + 3n^2 + 3n + 1 + 5n + 5
(n^3 + 5n) + 3n^2 + 3n + 6
6q + 3n^2 + 3n + 6
This reduces the problem down to proving that 3n^2 + 3n + 6 is a multiple of 6

3(n^2 + n + 2)
Now you just have to prove that n^2 + n + 2 is a multiple of 2, (is even).
 
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1. What is mathematical induction?

Mathematical induction is a proof technique used to prove that a statement is true for all natural numbers. It involves proving a base case (usually when n=1) and then showing that if the statement is true for some n=k, it is also true for n=k+1. This allows us to extend the truth of the statement to all natural numbers.

2. How do I use mathematical induction to solve equations?

To use mathematical induction to solve an equation, you first need to show that the statement (in this case, (n^3+5n)=6q) is true for the base case (usually when n=1). Then, you assume that the statement is true for some n=k and use this assumption to prove that it is also true for n=k+1. This process is repeated until you can conclude that the statement is true for all natural numbers.

3. What is the purpose of using mathematical induction?

The purpose of using mathematical induction is to prove that a statement is true for all natural numbers. This proof technique is particularly useful for proving statements about sequences, series, and recursive functions.

4. Can mathematical induction be used to prove any statement?

No, mathematical induction can only be used to prove statements that are true for all natural numbers. It cannot be used to prove statements about real numbers or complex numbers.

5. How can I tell if mathematical induction is the appropriate proof technique to use?

Mathematical induction is the appropriate proof technique to use when the statement you are trying to prove involves natural numbers and can be broken down into smaller cases. If the statement involves real numbers or complex numbers, other proof techniques such as direct proof or proof by contradiction may be more suitable.

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