function w = f1(z); w =  z; endfunction;
function w = f2(z); w =  z.^2; endfunction;
function w = f3(z); w =  z.^3; endfunction;
function w = f4(z); w =  z.^4; endfunction;

function vplot(x,y,f)
	z = x' * ones(y)  + ones(x)' * y * %i;
	fx = real(f(z));
	fy = imag(f(z));
	champ(x,y,fx,fy);
endfunction;

x=-0.9:0.2:0.9;
clf; vplot(x,x, real);
