How to stretch image in MATLAB online?

Hi, the image resulting from a calculation does not stretch properly across the window. How can this be done?

Thanks

[KSSV]

I think subplot is used there?

[Sergio Manzetti]

plot(X,Y(:,1))%,X,Y(:,2),X,Y(:,3),X,Y(:,1).* (2 + X .^ 2));