# Thread: graphing degree 3 eqn, help with roots.

1. ## graphing degree 3 eqn, help with roots.

Hi,

I am studying on my own. The textbook contains a graph of the following $f(x)=-x^3+x+1$.
I have successfully graphed the function, and note that there actually is one real root at about 1.3 or so.

Is there any way of finding this root algebraically. Perhaps even a link to a web site somewhere detailing how this root might be found? It probably has other complex roots too? I am really interrested in the real one.

Factoring doesn't get me far $-x(x^2-1)=-1$

Any direction would be much appreciated.

Thanks
Craig.

2. Originally Posted by craigmain
Hi,

I am studying on my own. The textbook contains a graph of the following $f(x)=-x^3+x+1$.
I have successfully graphed the function, and note that there actually is one real root at about 1.3 or so.

Is there any way of finding this root algebraically. Perhaps even a link to a web site somewhere detailing how this root might be found? It probably has other complex roots too? I am really interrested in the real one.

Factoring doesn't get me far $-x(x^2-1)=-1$

Any direction would be much appreciated.

Thanks
Craig.
The "Cubic Formula"