The following code refers to the system of differential equations in which only the first and second derivatives are included. How can the
zeroth derivative be referred to, for example, what if one of the equations was x'' = x*sqrt(x'^2+y'^2) rather than x'' = sqrt(x'^2+y'^2) – how could x be referred to? Writing
xy(0) for the 0th derivative or the position vector returns an error message but I am not sure how to modify the code. For example,
changing the first line to xy = zeros(6,1) does not help.
function xy=PackageMotion(t,x)% the differential equation soltuion
xy=zeros(4,1);% The paramter of the package
m=1; g=9.82; Cd=0.035;% The differential equation described in state space form
%xy(1)
xy(1)=x(2); %first derivative (velocity)
xy(2)=(-Cd*x(2)*sqrt(x(2)^2+x(4)^2))/m; xy(3)=x(4); xy(4)=(-Cd*x(3)*sqrt(x(2)^2+x(4)^2))/m-g; end
[SL: formatted the text of the question as text rather than code]
Best Answer