MHB Fixed Point Theorem: Estimating x* With x9 & x10

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The discussion revolves around the fixed point theorem applied to the function $\varphi:[-1,1] \to [-1,1]$ with a contraction constant of $L=0.8$. It confirms that the sequence defined by $x_{n+1}=\varphi(x_{n})$ converges to a unique fixed point $x^{*}$ for any starting point $x_0$ in the interval. The user calculates the error bounds for the 10th approximation, finding that $|x_{10}-x^{*}|\leq 0.004$. The conclusion reached is that the first option, $|x_{10}-x^{*}|<0.005$, is correct. The discussion ends with a confirmation of the calculations and agreement on the findings.
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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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!
 
I like Serena said:
Yep. All correct!

Great!Thank you! (Happy)
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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