Proving ${\psi}_{n}(x)\le F(n)$ by Induction

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In summary, the conversation is about proving by induction that ${\psi}_{n}(x)\le F(n)$ for a given function ${\psi}_{n}$ and interval $[a,b]$. The speaker suggests using a function $f(x,n)$ to prove the inequality, and has shown that it is true for $n=1$. They are hoping to extend this proof to show that ${\psi}_{n}(x)\le F(n)$ holds for all $n$.
  • #1
sarrah1
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Hello

is my proof be correct ?

I wish to prove by induction that ${\psi}_{n}(x)\le F(n)$ , $x\in[a,b]$ ... (1)

Let there exists a function $f(x,n)$ such that if ${\psi}_{n}(x)\le f(x,n) $ then ${\psi}_{n}(x) \le F(n)$ .

I know that (1) is true for $n=1$ i.e. ${\psi}_{1}(x)\le f(x,1)\le F(1)$ ,

and I was able to prove that

${\psi}_{n+1}(x)\le F(n+1)$ , $x\in[a,b]$

would this implies ${\psi}_{n}(x)\le F(n)$

thanks
 
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  • #2
sarrah said:
I wish to prove by induction that ${\psi}_{n}(x)\le F(n)$ , $x\in[a,b]$
Please provide the definitions of $\psi_n$, $F$, $a$ and $b$.
 

What is the purpose of proving ${\psi}_{n}(x)\le F(n)$ by Induction?

The purpose of proving ${\psi}_{n}(x)\le F(n)$ by Induction is to show that for every natural number n, the statement ${\psi}_{n}(x)\le F(n)$ is true. This can be done by proving the statement for a specific base case (usually n = 1) and then showing that if the statement holds for any given n, it also holds for n+1. By using mathematical induction, we can prove that the statement holds for all natural numbers n, thus establishing its validity.

What are the steps involved in proving ${\psi}_{n}(x)\le F(n)$ by Induction?

The steps involved in proving ${\psi}_{n}(x)\le F(n)$ by Induction are:
1. Establishing a base case: Choose a specific value of n (usually n = 1) and prove that the statement holds for that value.
2. Assuming the statement holds for n: Use this assumption to show that the statement also holds for n+1.
3. Concluding that the statement holds for all natural numbers n: By using mathematical induction, we can conclude that the statement holds for all natural numbers n, including the base case and n+1.

What are the common mistakes to avoid when proving ${\psi}_{n}(x)\le F(n)$ by Induction?

Some common mistakes to avoid when proving ${\psi}_{n}(x)\le F(n)$ by Induction are:
1. Not establishing a base case: It is important to prove the statement for a specific base case, otherwise the proof will not be complete.
2. Assuming the statement holds for n without proof: It is necessary to prove that the statement holds for n before using it to show that it holds for n+1.
3. Skipping steps: Each step in the induction proof is important and must be shown in order to reach a valid conclusion. Skipping steps can lead to an incomplete or incorrect proof.

Can ${\psi}_{n}(x)\le F(n)$ be proven by Weak Induction?

Yes, ${\psi}_{n}(x)\le F(n)$ can be proven by Weak Induction. In Weak Induction, we only need to prove that the statement holds for the base case and that it holds for n+1 assuming it holds for n. This is essentially the same as the steps involved in proving ${\psi}_{n}(x)\le F(n)$ by Induction. However, in Weak Induction, we are not required to prove that the statement holds for all natural numbers n, which is necessary in Mathematical Induction.

Can ${\psi}_{n}(x)\le F(n)$ be proven by Strong Induction?

Yes, ${\psi}_{n}(x)\le F(n)$ can be proven by Strong Induction. In Strong Induction, we not only have to prove that the statement holds for the base case and n+1, but also for all values in between. This can be useful when the statement depends on more than just the previous value, such as in the case of a Fibonacci sequence. However, Strong Induction is not always necessary and can sometimes be simplified to Weak Induction.

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