Fixed Point Theorem: Estimating x* With x9 & x10

In summary, the conversation discusses a formula for estimating the accuracy of a fixed point approximation, using a specific example with the 9th and 10th approximations. After using the formula, it is determined that answer 1) is correct, with a margin of error of 0.004. The conversation ends with confirmation and satisfaction with the results.
  • #1
evinda
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Hello! ;) I have a question.
Let $\varphi:[-1,1] \to [-1,1]$ with $L=0.8$ at $[-1,1]$, $\varphi$ has a unique fixed point $x^{*}$ and the sequence $(x_{n})$ with $x_{n+1}=\varphi(x_{n}) ,n=0,1,2,...$ is well defined and coverges to $x^{*}$ for any $x_{0} \in [-1,1]$.Then if the 9th approximation is $x_{9}=0.37282$ and the 10th is $x_{10}=0.37382$,we can say for sure that:
1) $|x_{10}-x^{*}|<0.005$
2) $|x_{10}-x^{*}|<0.001$
3) $|x_{10}-x^{*}|<0.002$

I used the formula $|x_{10}-x^{*}|\leq\frac{L}{1-L}|x_{n}-x_{n-1}|$ and found that $|x_{10}-x^{*}|\leq 0.004$.Is this right?So,is 1) the right answer? (Thinking)
 
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  • #2
evinda said:
Hello! ;) I have a question.
Let $\varphi:[-1,1] \to [-1,1]$ with $L=0.8$ at $[-1,1]$, $\varphi$ has a unique fixed point $x^{*}$ and the sequence $(x_{n})$ with $x_{n+1}=\varphi(x_{n}) ,n=0,1,2,...$ is well defined and coverges to $x^{*}$ for any $x_{0} \in [-1,1]$.Then if the 9th approximation is $x_{9}=0.37282$ and the 10th is $x_{10}=0.37382$,we can say for sure that:
1) $|x_{10}-x^{*}|<0.005$
2) $|x_{10}-x^{*}|<0.001$
3) $|x_{10}-x^{*}|<0.002$

I used the formula $|x_{10}-x^{*}|\leq\frac{L}{1-L}|x_{n}-x_{n-1}|$ and found that $|x_{10}-x^{*}|\leq 0.004$.Is this right?So,is 1) the right answer? (Thinking)

Yep. All correct!
 
  • #3
I like Serena said:
Yep. All correct!

Great!Thank you! (Happy)
 

1. What is the Fixed Point Theorem?

The Fixed Point Theorem is a mathematical theorem that states that for a continuous function, there exists at least one fixed point where the output of the function is equal to its input. In other words, there is a value where the function remains unchanged.

2. How is the Fixed Point Theorem used for estimating x*?

The Fixed Point Theorem can be used to estimate the value of x* by repeatedly applying the function to a starting value and observing the convergence of the outputs. The fixed point of the function will be the estimated value of x*.

3. What is the significance of using x9 and x10 in the Fixed Point Theorem?

In the context of estimating x*, x9 and x10 refer to the ninth and tenth iteration of applying the function to a starting value. These values are used to determine the convergence of the function and to estimate the fixed point of the function.

4. Is the Fixed Point Theorem applicable to all functions?

No, the Fixed Point Theorem is only applicable to continuous functions. This means that the function must have a smooth, unbroken graph with no sudden jumps or breaks.

5. What are the limitations of using the Fixed Point Theorem for estimation?

One limitation of using the Fixed Point Theorem for estimation is that it only provides an estimate of the fixed point and not the exact value. Additionally, it may not work for all functions, and the convergence of the outputs may be slow, making it a time-consuming process.

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