why the error is written here (Not enough input arguments.)

function dydt= project(t,psi)
M=5; m=0.5; R=0.5; tau=10*sin(100*t); F=10*cos(10*t) ; ddx=2;
dydt(1)=y(3);
dydt(2)=y(4);
dydt(3)=-(M*R^2*y(3) - 2*tau + 2*R^2*y(3)*m + 2*R*ddx*sin(y(1)))/(2*R*cos(y(1)))
dydt(4)=(M^2*R^2*y(3) + 3*M*R^2*y(3)*m + 2*ddx*sin(y(1))*M*R - 2*tau*M + 2*cos(y(1))*sin(y(1))*R^2*y(3)^2 + 2*R^2*y(3)*m^2 + 2*ddx*sin(y(1))*R*m + 2*F*cos(y(1))*R - 2*tau*m)/(2*R^2*cos(y(1))^2)
dydt=dydt';
end

Answer 1

[madhan ravi]

[t,y]=ode45(@project,[0 10],[0;0;0;0]) ; % you forgot to call the function with input arguments
plot(t,y(:,1))
figure
plot(t,y(:,2),'r')
figure
plot(t,y(:,3),'g')
figure
plot(t,y(:,4),'m')


function dydt= project(t,y)    % function definition
M=5; m=0.5; R=0.5; tau=10*sin(100*t); F=10*cos(10*t) ; ddx=2;
dydt=zeros(4,1);
dydt(1)=y(3);
dydt(2)=y(4);
dydt(3)=-(M*R^2*y(3) - 2*tau + 2*R^2*y(3)*m + 2*R*ddx*sin(y(1)))/(2*R*cos(y(1)));
dydt(4)=(M^2*R^2*y(3) + 3*M*R^2*y(3)*m + 2*ddx*sin(y(1))*M*R - 2*tau*M + 2*cos(y(1))*sin(y(1))*R^2*y(3)^2 + 2*R^2*y(3)*m^2 + 2*ddx*sin(y(1))*R*m + 2*F*cos(y(1))*R - 2*tau*m)/(2*R^2*cos(y(1))^2);
end

[Mustafa Alhandhali]

it is written

Function definitions are not permitted in this context.

[madhan ravi]

save the function as project.m and then just try my answer with the first 8 lines without function definition.

[Mustafa Alhandhali]

when i try to save the function it witten "Not enough input arguments."

[madhan ravi]

man you are not obviously saving you are trying to run the function by clicking the green button..

https://in.mathworks.com/matlabcentral/answers/3478-save-function-in-matlab

[Mustafa Alhandhali]

how i can find relation (psi with time)

and y with time

[madhan ravi]

Since I don't have your equation in latex form you can easily find the relationship dydt represents the equations likewise for the rest and every equation are plotted against time.

[Mustafa Alhandhali]

ok thank you so much

[madhan ravi]

Anytime :)

[Mustafa Alhandhali]

last quastion :(

if i want to replace the function of F( F=10*cos(10*t))

to pulse functin first and in another exmple to unit step funnction

how i can write the code

note: i want any exapmles of pulse functin and unit step funnction which can i write it here