Trouble plotting a 3D meshgrid

I need to plot a 3D surface plot using a meshgrid, but it keeps saying not enough input arguements?

x=[-4:1:4];   y=[-3:1:3];   

z=sqrt((x.^2/4)+2*sin.^2*(0.7*y));

mesh(x,y,z)

Answer 1

[Dyuman Joshi]

[x,y]=meshgrid(-4:0.1:4,-3:0.1:3); %Making the difference smaller to get a smoother mesh
z=sqrt((x.^2/4)+2*sin(0.7*y).^2);
mesh(x,y,z)