How to plot this ellipse

I tried this; but did not get answer like in textbook. Please see my code and image.Kindly help

[x,y] = meshgrid(-300000:10000:600000);

z=(x.^2-15.156*x*y+229.7*y.^2+488.8*1000.0*1000.0+6844000*y-4.752*10.^10);

surf(x,y,z)

,y,z)

[Walter Roberson]

if you have the symbolic toolbox you can fimplicit()

[Keshav]

thanks a lot.

Answer 1

[KSSV]

syms s1 s2 
t = 0 ;
eqn = s1^2-15.156*s1*s2+229.7*s2^2+488.8*t^2+6844000*s2==4.752*10^10 ;
fimplicit(eqn,[-600000 200000 -100000 20000])

[Keshav]

Thanks a lot. How can I run T=1000 and plot both ellipses in the same plot?

[KSSV]

syms s1 s2 

t = 0 ; 
eqn = s1^2-15.156*s1*s2+229.7*s2^2+488.8*t^2+6844000*s2==4.752*10^10 ;
h = fimplicit(eqn,[-600000 300000 -100000 20000]) ; 

x1 = h.XData ; y1 = h.YData ; 

t = 10000 ; 
eqn = s1^2-15.156*s1*s2+229.7*s2^2+488.8*t^2+6844000*s2==4.752*10^10 ;
h = fimplicit(eqn,[-600000 300000 -100000 20000]) ; 
x2 = h.XData ; y2 = h.YData ; 

close all
figure
hold on
plot(x1,y1,'.r') ;
plot(x2,y2,'.b')

[Keshav]

Thanks!!