# Factoring Polynomials

Collin D collin.day.0 at gmail.com
Fri Dec 19 01:59:04 CET 2008

```On Dec 18, 4:41 pm, "James Mills" <prolo... at shortcircuit.net.au>
wrote:
> On Fri, Dec 19, 2008 at 10:11 AM, Gabriel Genellina
>
> <gagsl-... at yahoo.com.ar> wrote:
> > En Thu, 18 Dec 2008 17:37:35 -0200, <collin.da... at gmail.com> escribió:
>
> >> I am trying to write a simple application to factor polynomials. I
> >> wrote (simple) raw_input lines to collect the a, b, and c values from
> >> the user, but I dont know how to implement the quadratic equation
>
> >> x = (-b +or- (b^2 - 4ac)^1/2) / 2a
>
> Why is this so hard ? This is simple simple
> expression. Reading through the Python
> tutorial and reading up on how to define
> functions is all you need! :)
>
> Here goes:
>
> >>> def f(a, b, c):
>
> ...     x = (-1 * b) + ((b**2 - (4 * a * c)) / (2 * a))
> ...     return (-1 * x), x
> ...
>
> >>> f(1, 2, 3)
> (6, -6)
>
> cheers
> James

Hiya James!

Just one small problem with your equation above...
The quadratic formula is:
x = -b +or- (b**2 - (4 * a * c))^1/2 / 2a

You just forgot the square root which makes quadratic a bit more
complicated.
You would have to download and import sqrt() from numpy or **.5

Also.. I need to build in functionality so the user does not have to
directly call the function like:
f(a,b,c)

Instead.. they should be able to just raw_input their values.
Also.. as with some of the examples above its a good idea to analyze
the discriminant to make sure we have a real solution.
Of course.. thats all pretty simple to build in. Thanks a lot!

```

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