function F = vdpfcn1000(t,y)
%
% This function is the right hand side of
% the equation y' = F(t,y)
% F must be returned as a column vector
% y is a column vector in this function
%
mu=1000;
F = [ y(2,:); (mu*(1-y(1,:).^2).*y(2,:) - y(1,:))];