On Sunday 30 March 2008 19:34, Adam Majewski wrote:
> > You're converting expression to polar form incorrectly.
>
> Yes but where is my error ?
>> You should get r=r(theta) from {r=r(t),theta=theta(t)} by excluding
>> parameter t (which is not an argument).
>
> I have changed name "t" to "theta" ( I didn't know that it has meaning)
> but it gives the same curve.
No, it hasn't special meaning for Maxima plotter. t is just not an polar angle
here. As I wrote, standard way is to exclude t and get r=r(theta) from
{r=r(t),theta=theta(t)}, but in this case you should start from known polar
equation.
> Anyway, it's better to start from known polar equation of cardioid
>
> > r = a (1-cos(theta)).
> >
> > So, parametric equations are ...
>
> Yes parametric form works well.
> Can it be done in polar form ?
> (:-))
As I wrote, a = 1/2. Just read my message more attentive.
--
Alexey Beshenov <al at beshenov.ru>
http://beshenov.ru/
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