2D contour plot

I have two fucntions with identical independent variable x. I need to draw a 2D contour plot for that two fucntions. But my code is not runnig. Pl somebody help me.

syms x
y1=x^.3+x+1;
y2=4.*x.^2;
x=linspace(0,5,30)
[X]=meshgrid(x);
F1=y1(X);
F2=y2(X);
contourf(F1(X), F2(X))

This code is not runnig. I need to get a filled contour with F1 and F2.

Answer 1

[Walter Roberson]

Guessing about what you might maybe mean:

syms x
y1(x)=x^.3+x+1;
y2(x)=4.*x.^2;
x=linspace(0,5,30);
[X]=meshgrid(x);
F1=y1(X);
F2=y2(X);

subplot(1,2,1)
contourf(x, x, F1);
title('y1')
axis equal
subplot(1,2,2)
contourf(x, x, F2);
title('y2')
axis equal

[AVM]

@walter: Thanks for your reply. But I need to draw the 2D contour by allowing y1 as the vertical axis( y axis) and y2 along horizontal axis(x axis).

[Walter Roberson]

If you do that... then what is the z value? Contours require different values of z

[AVM]

can I consieder X as Z in that case?

[AVM]

Actually I need to see as x changes, then what is corresponding chages of y2 as y1 will be changing. I need to know the behaviour of y2 as y1 changes from a 2D contour plot.

[Walter Roberson]

Actually I need to see as x changes, then what is corresponding chages of y2 as y1 will be changing.

All I can think of that you might mean for that would be like

dy1 = diff(y1);
dy2 = diff(y2);
fplot(dy2-dy1, [0 5])

Your y1 and y2 are each single dimensional; there is no reason to be using meshes and contour plots with them.