ode45 inside calling funciton error

I have forced.m funciton and i want to use inside ode45 funciton but doesn't work i have error

Not enough input arguments.

Error in forced (line 2)

yp = [y(2);(((f/m)*sin(W*t))-((c/m)*y(2))-((k/m)*y(1)))];

Error in Untitled2 (line 11)

[t,y]=ode45(forced, tspan, y0);

main code

tspan=[0 5]; 
y0=[0.02;0];
x=y(:,1);
f=200;
k=200;
m=2;
W=sqrt(k/m);
er=0.1;
c=2*er*W*m;

[t,y]=ode45(forced, tspan, y0);
plot(t,y(:,1)); grid on xlabel(‘time’)
ylabel('Displacement')
title('Displacement Vs Time') 
hold on;

forced.m

function yp = forced(t,y)
yp = [y(2);(((f/m)*sin(W*t))-((c/m)*y(2))-((k/m)*y(1)))];

Answer 1

[Star Strider]

All the arguments the function needs must be passed to it as additional parameters.

See the documentation section on Passing Extra Parameters.

tspan=[0 5]; 
y0=[0.02;0];
% x=y(:,1);
f=200;
k=200;
m=2;
W=sqrt(k/m);
er=0.1;
c=2*er*W*m;

[t,y]=ode45(@(t,y)forced(t,y,f,k,m,W,er,c), tspan, y0);
plot(t,y(:,1)); 
grid on 
xlabel('‘time’')
ylabel('Displacement')
title('Displacement Vs Time') 
hold on;

function yp = forced(t,y,f,k,m,W,er,c)
yp = [y(2);(((f/m)*sin(W*t))-((c/m)*y(2))-((k/m)*y(1)))];
end

.

[Star Strider]

I used the initial values as provided in the posted code.

Flipping the initial conditions vector and plotting the function and the derivative ...

tspan=[0 5]; 
y0=[0.02;0]

y0 = 2×1

0.0200 0

y0 = flip(y0)

y0 = 2×1

0 0.0200

% x=y(:,1);
f=200;
k=200;
m=2;
W=sqrt(k/m);
er=0.1;
c=2*er*W*m;

[t,y]=ode45(@(t,y)forced(t,y,f,k,m,W,er,c), tspan, y0);
plot(t,y); 
grid on 
xlabel('‘time’')
ylabel('Displacement')
title('Displacement Vs Time') 
hold on;
legend('y_1','y_2', 'Location','best')

function yp = forced(t,y,f,k,m,W,er,c)
yp = [y(2);(((f/m)*sin(W*t))-((c/m)*y(2))-((k/m)*y(1)))];
end

... gives the same result.

The errors are in the original code, not my corrections to it (that allowed it to run without error). Neither of the integrated values (the displacement or velocity) are close to the desired plot.

In order to correct the error, I would need to see the differential equations that are being coded here.

.

[Mert Dark]

This is the problem code and why my code does not same plot this article code?

[Torsten]

Then either the plot in your assignment is wrong or the constants f,k,m,W,er and/or c used therein differ from yours.

[Star Strider]

@Torsten — Thank you!

@Mert Dark — The problem assignment statement is clearly misleading, because function files do not inherit any variables from the calling script, although an anonymous function version of ‘yp’ definitely would (if written in the code after the other variables were defined). That the other variables were not listed as arguments (as in my code) leads me to believe that whoever wrote the problem assignment is engaged in a significant amount of wishful thinking. It would be worthwhile to see the actual code that produced the plot (or plots) this code is supposed to produce. What are the other parameters? What values of the parameters produced the desired plot?

.

[Mert Dark]

@Star Strider other parameters here photo1

[Mert Dark]

@Star Strider other parameters here photo2

[Mert Dark]

@Star Strider but i choose this paraeters just double all

[Torsten]

W = 2*sqrt(k/m)

instead of

W = sqrt(k/m)

and consequently

c = er*W*m

instead of

c = 2*er*W*m

in your code.

[Star Strider]

@Torsten — Thank you!

Away for a few minutes here.

Answer 2

[Mert Dark]

but i need this graph