[Maxima] Solving equation numerically
robert.dodier at gmail.com
Fri Jan 25 00:37:21 CST 2008
On 1/24/08, Dan Soendergaard <dan1990 at gmail.com> wrote:
> I'm completely new to Maxima. I use it as a Mathcad replacement in
> Linux which I am truly happy about.
I would be interested to hear if there is anything in Mathcad which
you miss in Maxima.
>Today, I was in class given the
> task to solve the given equation for x,
> sin(x) + x = 2.5*x + 1.5
> In Maxima I entered,
> > solve(sin(x) + x = 2.5*x + 1.5, x);
> which gives me,
> x = 5 * sin(x) + 7.5
Hmm. x = 5 * sin(x) + 7.5 doesn't appear to be equivalent
to sin(x) + x = 2.5*x + 1.5 ... Is there a typo somewhere?
> Isn't it possible to solve this equation numerically? I know that I
> should get three results for x since there are three intersection
I think you can plot the stuff returned by solve,
plot2d ([5*sin(x) + 7.5, x], [x, 0, 10]);
let's say, and use that to guess a range or ranges for find_root.
(find_root only tries to find one root.)
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