Why am i getting error too many input arguments ?

I have a problem to solve an ODE with any methods. The question was The motion of a damped spring-mass system is described by the following ordinary differential equation:

m fraction numerator d squared x over denominator d t squared end fraction plus c fraction numerator d x over denominator d t end fraction plus k x equals 0

where x = displacement from equilibrium position, t = time, m = 20 kg is the mass, k = 20 N/m is the spring constant, c = the damping coefficient. The damping coefficient c takes on three values of 5 (underdamped), 40 (critically damped), and 200 (overdamped). The initial velocity is zero, and the initial displacement x = 1 m.

Develop an M-file to solve this equation using a numerical method (choose any method you prefer most) over the time period 0 less or equal than t less or equal than 15 space s. Plot the displacement versus time for each of the three values of the damping coefficient on the same plot."

Then I make my 3 codes , first one is the euler methods

function [t,y] = eulode (dydteulode,tspan,y0,h)
%eulode : EULER ODE SOLVER
% [t,y] = eulode (dydt,tspan,y0,h,p1,p2,...) :
        % use Euler method to integrate ODE 
%input:
 %dydt = name of the M-file that evaluates ODE
 %tspan = [ti, tf] where ti and tf = initial and final values of
 %independent variable
%y0= initial value of dependent variable 
%h= step size 
%p1,p2,...= additional parameters used by dydt
%output:
 % t= vector of independent variable
 % y= vector of solution for dependent variable

   ti= tspan(1);tf = tspan(2);
   t = (ti:h:tf)'; 
   n = length(t);
   %if necessary, add an additional value of t 
   % so that range goes from t = ti to tf
   if t(n)<tf 
       t(n+1) = tf; 
       n = n+1; 
   end
   y(1,:)= y0; %preallocate y  to improve accuracy
   for i = 1:n-1 %implement Euler's method 
       hh = t(i+1)-t(i);
       k  = feval(dydteulode,t(i),y(i,:))';
       y(i+1,:) = y(i,:)+k*hh;
   end

then the function for the graphic plot

function []=graphploteulode()
clear,clc,clf
k= 20; m=20; tspan= [0:1/4:15]; y0= [1 0];
%defiining constants and initial condition given in the problem
%tspan i.e. time is incremented with step size 1/4
[t1,y1]= eulode(@dydteulode,tspan,y0,1/4,m,k,5);
%integrating for underdamped condition 
[t2,y2]= eulode(@dydteulode,tspan,y0,1/4,m,k,40);
%integrating for critically damped condition
[t3,y3]= eulode(@dydteulode,tspan,y0,1/4,m,k,200);
%integrating for overdamped condition 
plot (t1,y1(:,1),t2,y2(:,1),':',t3,y3(:,1),'--')
legend ('underdamped','critically damped','overdamped','location','best')
title ('Displacements for mass-spring system')
xlabel('t(s)'),ylabel('x(m)')
%generating required plot
end

and last the equation itself

function dy = dydteulode (t,y,m,k,c)
dy= [y(2);-(c*y(2)+k*y(1))/m];
end

but when I run the graphplot i got an error which is to many input arguments and it points to my code on line6 in graphplot which is [t1,y1]= eulode(@dydteulode,tspan,y0,1/4,m,k,5);

I don't know why is this happened, please help thank you.

Answer 1

[Stephen23]

Here is the function defintion of eulode (including superfluous space between function name and parenthesis):

function [t,y] = eulode (dydteulode,tspan,y0,h)

When I count the number of input argument there are four of them. This is how you call eulode:

[t1,y1]= eulode(@dydteulode,tspan,y0,1/4,m,k,5);

When I could the input arguments there are seven of them. You defined the function with four input arguments, and then call it with seven inputs. This is an error. To pass extra arguments to any function you could use nested functions or define an anonymous function, exactly as the MATLAB documentation shows:

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

Answer 2

[Walter Roberson]

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html