# Math Help - numerical analisys question..

1. ## numerical analisys question..

http://i48.tinypic.com/2yzd213.jpg

how they got g1 g2 g3
?

2. Originally Posted by transgalactic
http://i48.tinypic.com/2yzd213.jpg

how they got g1 g2 g3
?
They are just different rearrangemants of $x^3-x-5=0$ into the form $x=g(x)$, presumably to show that formula iteration converges for some but not others.

$g_1(x)$ comes from the rearrangement $x=x^3-5$

$g_2(x)$ comes from the rearrangement $x^3=x-5$, so $x= \sqrt[3]{x-5}$

$g_3(x)$ comes from the rearrangement $x(x^2-1)-5=0$ so $x=\frac{5}{x^2-1}$

CB

3. ok i solved a similar equation:
$x^3+2x^2+4-x=0$
$g1=x^3+2x^2+4$

why for g1 L=0.5
how to find L for other g
what is the meaning of L?