plotting quadratic equation and curve fittting

im kinda of struck how to plot quadratic function for different x and y values.the equation is (x^25)+(y^3)-(6*x^24*y) for different values of x =[-10,10] and y=[-10,10] and do a polyfit for the obtained point

Answer 1

[Star Strider]

The plot is straightforward:

fcn = @(x,y) (x.^25)+(y.^3)-(6*x.^24.*y);

[X,Y] = meshgrid(-10:0.5:10);

figure(1)
meshc(X, Y, fcn(X,Y))
grid on
xlabel('X')
ylabel('Y')

I do not know the reason you would want to fit this with polyfit. You already have the equation for the surface.

[Avinash Tallapaneni]

i wanted points for different vales of x and y if we plug x's and y's in eqn we will get value and that value needs to be plotted in graph ,so we will get number of points from that equation and i want a curve that passed through these points

ps i dont need 3d graph , i need values in cs x values for horizontal axis and y values for vertical axis thankyou

[Star Strider]

Please clarify what you want. Your original Question and the first part of your Comment asked for exactly what my code provided.

I do not understand your ‘ps’. It does not make sense.

[Avinash Tallapaneni]

i am sorry but i didnt run the code ,i just saw the code and asked ,now i runned the code i need only the curve lines (xy plane) not the surface how to do that?

[Star Strider]

The xy plane the function uses are defined by the ‘X’ and ‘Y’ outputs of meshgrid.

[Avinash Tallapaneni]

my friend i am new to matlab maybe i am conveying you wrong , i know that the surface is projected on plane so we get those curves.i need only the highlighted part not the surface maybe a transparent surface but a visible color curves ,is that possible? thankyou

[Star Strider]

The plot you want is the contour function to only plot the contours.

The plot you show was produced by the meshc function. It draws the surface and the contours.

[M]

A quite good. but cammand for equation, F(x) = x^3+ 2x+1

[Star Strider]

@M — Your function is not appropriate for this code, since it has only one variable and this code requires functions with two variables.