I am unable to run this program.

second_oder_ode

Error using odearguments
SECOND_ODER_ODE/RHS returns a vector of length 3, but the length of initial conditions vector is 2. The vector returned by SECOND_ODER_ODE/RHS and the initial conditions vector must have the same number of elements.

Error in ode45 (line 104)
odearguments(odeIsFuncHandle,odeTreatAsMFile, solver_name, ode, tspan, y0, options, varargin);

Error in solution>second_oder_ode (line 19)
[t,x]=ode45( @rhs, t, [initial_x initial_dxdt] );

function second_oder_ode 

% SOLVE  d^2x2/dt^2 = (k(Asin(wt)-x2)-cA(dx/dt)/h)/m 
% initial conditions: x(0) = 0, x'(0)=0 

t=0:0.001:1;% time scale 

initial_x    = 0; 
initial_dxdt = 0; 
c=0.001;
h=0.01;
k=100;
m=1;
w=10;
A=2;

[t,x]=ode45( @rhs, t, [initial_x initial_dxdt] ); 

plot(t,x(:,1)); 
xlabel('t'); ylabel('x'); 

    function dxdt=rhs(t,x) 
        dxdt_1 =  x(2); 
        dxdt_2 =  (k*(A*sin(w*t)-x)-(c*A/h)*x(2))/m; 
        
        dxdt=[dxdt_1; dxdt_2]; 
    end 
end

[Dyuman Joshi]

Please share the mathematical definition of the equation you are trying to solve.

Answer 1

[Sam Chak]

Hi @Puja

I've indicated the location where you should apply a fix to it.

second_oder_ode 

function second_oder_ode 
    % SOLVE  d^2x2/dt^2 = (k(Asin(wt)-x2)-cA(dx/dt)/h)/m 
    % initial conditions: x(0) = 0, x'(0)=0 
    t=0:0.001:1;% time scale 
    initial_x    = 0; 
    initial_dxdt = 0; 
    c=0.001;
    h=0.01;
    k=100;
    m=1;
    w=10;
    A=2;
    [t,x]=ode45( @rhs, t, [initial_x initial_dxdt] ); 
    plot(t,x(:,1)); 
    xlabel('t'); ylabel('x'); 
    
    function dxdt=rhs(t,x) 
        dxdt_1 =  x(2); 
        dxdt_2 =  (k*(A*sin(w*t)-x(1))-(c*A/h)*x(2))/m; 
        %                        ^^^^
        dxdt=[dxdt_1; dxdt_2]; 
    end 
end