2022-11-15 18:34:38 +0100 received badge ● Famous Question (source) 2022-11-15 18:34:38 +0100 received badge ● Notable Question (source) 2018-01-29 16:19:21 +0100 received badge ● Taxonomist 2017-09-04 22:30:58 +0100 received badge ● Popular Question (source) 2016-09-05 04:16:48 +0100 received badge ● Famous Question (source) 2016-01-09 21:43:00 +0100 received badge ● Popular Question (source) 2013-12-25 16:07:47 +0100 received badge ● Notable Question (source) 2013-06-21 10:47:38 +0100 received badge ● Popular Question (source) 2012-05-07 10:43:17 +0100 answered a question contour plot not working as expected Oh, I see. Thank you very much! BR M 2012-05-07 04:34:12 +0100 asked a question contour plot not working as expected Hi all, I am looking at ways to determine the sign of an angle between a reference vector (a,b) and any other vector(x,y) of the plane. To do so, I have decided to use the determinant of the matrix: [[a b],[x y]] which equals ax-by. I wanted then to check that the formula works by displaying the plane area which positive and negative signs using the contour_plot. Here is my question: Why is the 3rd graph not showing 2 horizontal areas instead of the vertical displayed? var('x y') f(x,y,a,b)=(a*y-b*x)/abs(a*y-b*x) plota1b1=contour_plot(f(x,y,1,1),(-10,10),(-10,10),cmap='jet',colorbar=true) plota0b1=contour_plot(f(x,y,0,1),(-10,10),(-10,10),cmap='jet',colorbar=true) plota1b0=contour_plot(f(x,y,1,0),(-10,10),(-10,10),cmap='jet',colorbar=true) show(plota1b1) show(plota0b1) show(plota1b0)  Thanks 2012-04-24 15:25:47 +0100 asked a question Recursive max_symbolic??? Hi Over a (x,y) space, I have n functions resp f_1(x,y), f_2(x,y), ..., f_n(x,y) and I would like to create g(x,y) =max(f_1(x,y), f_2(x,y), ..., f_n(x,y), constant) I now know it is possible to use max_symbolic with 2 functions, but then if I have say 100 of them, it gets clumpsy. Does anyone know a way to do that? Thanks 2012-04-20 10:59:08 +0100 asked a question Function value at parametric path Hi, How can I get the value of a 2D function, say f(x,y)=x^3+y^3, along the path determined by a parametric function, say M(x(t)=cos(t),y(t)=sint(t))? 2012-04-19 15:52:55 +0100 asked a question min(f,g) where f and g take two variables Hi Is it possible to create a function h(x,y) that would be the minimum (or maximum) of any two other 2-variable functions? Like h(x,y)=max(f(x,y),g(x,y))? (this does not work) This seems to be a rather useful function but I can't seem to find it. any ideas? Thanks N. 2012-04-18 05:39:09 +0100 answered a question Defining a function and forcing max or min value Yes, that's what I wanted to achieve. Thank you very much! It also works with 2 functions, which is what I needed in the end. Thanks again f(x)=cos(x) g(x)=sin(x) h(x)=max_symbolic(f(x),g(x)) a=plot(f,-pi,pi) b=plot(g,-pi,pi,color='green') c=plot(h,-pi,pi,color='red') show(a+b+c) 2012-04-17 13:16:36 +0100 received badge ● Student (source) 2012-04-17 09:09:01 +0100 received badge ● Editor (source) 2012-04-17 09:08:11 +0100 asked a question Defining a function and forcing max or min value Hi, Is it possible to define a funtion, say f, and have it be the maximum (or minimum) of another function and a constant? Example (pseudo-script): if g(x)=log(abs(x)), let f(x)=g(x) if g(x)>0, and f(x)=0 for all g(x)<0 Thanks N.C.