How to write an M-file that uses ezplot to display a graph and a circle on the same figure ?

Question

评论： Star Strider 2016-3-11

Write an M-file that use ezplot to display the graph of 2x^2+xy+y^4=1 and the circle x^2+y^2=1, on the same figure.

with graphing window where x and y vary from -1.2 to +1.2. help please

Answer 1

Star Strider 2016-3-11

编辑：Star Strider 2016-3-11

This is obviously a homework assignment.

Create anonymous functions for both of your functions, perhaps calling them ‘p’ for the polynomial and ‘c’ for the circle,
Plot the polynomial as ‘ezplot(p, [xmin xmax ymin ymax])’ and the same for the circle,
See the documentation for the hold function,
See the documentation for the axis function (so the circle looks like a circle and not an ellipse).

That should give you your plot.

syms x y;

z=2.*x.^2+x.*y+y.^4-1; d=x.^2+y.^2-1;

 ezplot3(z,p,[-1.2 1.2]);
 % i did that and keep showing error on the ezplot , am i forgetting something ?

Star Strider 2016-3-11

I can’t make it work with symbolic functions either. That’s the reason I suggested using anonymous functions. I can make it work with them.

I rarely use ezplot (and it’s obsolete starting with R2016a), so I only use it with anonymous functions.