draw regions defined by inequality



El mi?, 26-12-2012 a las 16:05 +0100, Adam escribi?:
> Hi,
> 
> How can I draw points z defined by inequality :
> 
> 
> (C*z^6)/z < 0 ;
> 

I think you mean (C*z^6)/z \in (-\infty, 0)

This is equivalent to 

Im(C*z^5) = 0 and Re(C*z^5) < 0

The first condition is a curve and the second is a region of the plane.
The intersection is also curve. You can plot both sets separately; here,
the curve is in blue and the region is filled in red. You can get an
idea on the intersection.

load(draw) $
C : 15.31858176724506-17.39503852518886*%i $
expr: C*(x+y*%i)^5 $
define(rp(x,y), realpart(expr)) $
define(ip(x,y), imagpart(expr)) $

draw2d(
    terminal = pngcairo,

    /* Re(C*z^5) < 0 */
    x_voxel = 50,
    y_voxel = 50,
    region(rp(x,y) < 0,x,-1,1,y,-1,1),

    /* Im(C*z^5) = 0 */
    line_width = 3,
    ip_grid=[100,100],
    implicit(ip(x,y) = 0,x,-1,1,y,-1,1) ) $

I am not sure this is what you need.

--
Mario