Induction for series of squares

In summary, induction for series of squares is a mathematical proof technique used to prove statements involving natural numbers. It involves proving a base case and using the assumption that the statement is true for a given number to prove it is also true for the next number. This method is useful for proving statements with recursive or repetitive patterns. There are two forms of induction - strong and weak - which differ in the assumption made. However, induction for series of squares can only be used for statements involving natural numbers and not for other mathematical concepts. Common mistakes when using this method include not properly proving the assumption and using strong induction when weak induction would suffice. It is also important to ensure the base case is correct and the statement is actually true for the initial number.
  • #1
KOO
19
0
Prove that for all nEN

1^2 + 3^2 + 5^2 + ... + (2n-1)^2 = (4n^3 - n) / 3My Solution)


If n = 1, 4(1)^3 - 1 / 3 = 1 so base case holds.

Assume 1^2 + 3^2 + ... + (2k-1)^2 = (4k^3 - k) / 3

What next?
 
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  • #2
Well, then, obviously:

$1^2 + 3^2 + 5^2 + \cdots + (2k - 1)^2 + (2k + 1)^2 = \dfrac{4k^3 - k}{3} + (2k + 1)^2$

$= \dfrac{4k^3 - k}{3} + \dfrac{12k^2 + 12k + 3}{3}$

$= \dfrac{4k^3 + 12k^2 + 12k + 4 - k - 1}{3}$

$= \dfrac{4(k+1)^3 - (k+1)}{3}$
 

FAQ: Induction for series of squares

What is induction for series of squares?

Induction for series of squares is a mathematical proof technique used to prove that a statement is true for all natural numbers. It involves proving a base case, typically when n=1, and then using the assumption that the statement is true for n=k to prove that it is also true for n=k+1.

How is induction for series of squares used?

Induction for series of squares is used to prove mathematical statements that involve natural numbers, such as properties of sums, products, and sequences. It is particularly useful for proving statements that have a recursive or repetitive nature.

What is the difference between strong and weak induction for series of squares?

In strong induction for series of squares, the assumption is made that the statement is true for all natural numbers up to k, rather than just for k. Weak induction only assumes that the statement is true for k. Strong induction is more powerful, but both methods are valid and can be used interchangeably.

Can induction for series of squares be used to prove all mathematical statements?

No, induction for series of squares can only be used to prove statements that involve natural numbers. It cannot be used to prove statements about real numbers or other mathematical concepts.

What are some common mistakes when using induction for series of squares?

One common mistake is assuming that the statement is true for n=k+1 without properly proving it using the assumption that it is true for n=k. Another mistake is using strong induction when weak induction would suffice. It is also important to make sure that the base case is correct and that the statement is actually true for n=1.

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