The map X(n+1) = [X(n)]^3 + a*Xn has a fixed point at the origin. For what

values of a is this fixed point stable?

So stable meaning is will always gradually be along the line of 0?

So would a have to be -[X(n)]^2

?

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- October 24th 2009, 04:13 PMchriscstable fixed point
The map X(n+1) = [X(n)]^3 + a*Xn has a fixed point at the origin. For what

values of a is this fixed point stable?

So stable meaning is will always gradually be along the line of 0?

So would a have to be -[X(n)]^2

? - October 25th 2009, 12:25 AMCaptainBlack

A point is a stable fixed point if when you start near the point all subsequent points are also near the point.

Near zero your difference equation becomes:

=

This is clearly unstable when . It is also unstable when and stable when (but to show this you need to look at the sign of the non-linear term), and it is stable if

CB