# Math Help - dynamical system

1. ## dynamical system

hey, can anybody help?
i have a 1 dimensional dynamical system in which x is greater than 0
x(with a dot on top)=f(x)=1-(5x^2)+(4x^4)
how to i solve f(x*)=0 and find its fixed points?
thanks

$0 = 4\cdot x^4 - 5\cdot x^2+1$
Let $u = x^2$
Then $0 = 4\cdot u^2 - 5\cdot u+1$
$u = \frac {5 \pm \sqrt{25-9}}{8}$
$x = \pm\sqrt {u} = \pm 1 or \pm \frac{1}{2}$