Prove f(n) is a product of two consecutive positive integers for all n

In summary, proving that f(n) is a product of two consecutive positive integers for all n is important as it shows a pattern in the function and can be used to make predictions for any value of n. This is typically done using mathematical induction, where the base case is shown to be true and then it is proven that the statement holds for the next value. This proof has various real-life applications in fields such as number theory, algebra, statistics, and computer programming.
  • #1
Albert1
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0
$f(n)=\underbrace{111--1}\underbrace{222--2}$
$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,n$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,n$
prove:$f(n)$ is a product of two consecutive positive integers for all $n\in N$
 
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  • #2
Albert said:
$f(n)=\underbrace{111--1}\underbrace{222--2}$
$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,n$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,n$
prove:$f(n)$ is a product of two consecutive positive integers for all $n\in N$

as n consecutive 1's is $\frac{10^n-1}{9}$ using GP
we have $f(n) = 10^n(\frac{10^{n}-1}{9} + 2 * (\frac{10^{n}-1}{9})$
$= \frac{10^n(10^{n} - 1) + 2(10^n-1)}{9}$
$= \frac{10^{2n} + 10^n -2}{9}$
$=\frac{(10^n-1)(10^n+2)}{9}$
= $(\frac{10^n-1}{3})(\frac{10^n+2}{3})$
= $(\frac{10^n-1}{3})(\frac{10^n-1}{3}+1)$
now $10^n$ leaves a raminder 1 when divided by 3 so $10^n-1$ is divsible by 3 and hence noth the terms above are
integers and difference is one.
 

FAQ: Prove f(n) is a product of two consecutive positive integers for all n

What does it mean for f(n) to be a product of two consecutive positive integers?

When we say that f(n) is a product of two consecutive positive integers, it means that f(n) can be written as the multiplication of two positive integers that are consecutive, meaning they are right next to each other. For example, f(3) = 6, which can be written as 2 x 3, where 2 and 3 are consecutive positive integers.

Why is it important to prove that f(n) is a product of two consecutive positive integers for all n?

This proof is important because it shows that the function f(n) follows a specific pattern and can be written in a simplified form. It also helps in understanding the behavior of the function and can be used to make predictions for any value of n.

What is the general approach to proving that f(n) is a product of two consecutive positive integers for all n?

The general approach to proving this statement is by using mathematical induction. This involves showing that the statement is true for the base case, usually n = 1, and then assuming that it is true for some arbitrary value of n (k) and proving that it is also true for the next value (k+1). This process is repeated until it can be concluded that the statement is true for all values of n.

Can you provide an example of a proof for f(n) being a product of two consecutive positive integers for all n?

As an example, let's take the function f(n) = n(n+1). For the base case, when n = 1, f(1) = 1(1+1) = 2, which can be written as the product of 1 and 2, which are consecutive positive integers. Now, assuming that f(k) = k(k+1) can be written as a product of two consecutive positive integers, we can show that f(k+1) is also a product of two consecutive positive integers. We have f(k+1) = (k+1)(k+2) = k(k+1) + (k+1)(k+2) = f(k) + (k+1)(k+2) = k(k+1) + (k+1)(k+2). By factoring out (k+1), we get f(k+1) = (k+1)(k+2) = (k+1)(k+2), which shows that f(k+1) can also be written as a product of two consecutive positive integers. Therefore, by the principle of mathematical induction, we can conclude that f(n) is a product of two consecutive positive integers for all n.

What are some real-life applications of proving that a function is a product of two consecutive positive integers for all n?

This statement can be applied in various fields such as number theory, algebra, and statistics. For example, in number theory, this proof can help in finding the factors of a given number and identifying prime numbers. In algebra, it can be used to simplify algebraic expressions and solve equations. In statistics, it can be applied in regression analysis to identify trends and patterns in data. Additionally, this proof can also be used in computer programming to optimize algorithms and improve efficiency.

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