hi guys . i am trying to solve Ode but solution stuck at some point . i tried ode45 & ode15s but problem is still present

function dx=pendulum_eom(t,x)
% pendulum parameters 
M=1.5;
m=.5;
l=.4;
k1=0;  % linear velocity friction coefficient 
k2=.02;  % rotional velocity friction coefficint
g=9.81;
F=0;    % force applied to the cart
%-----%
dx=zeros(4,1);  % system states
% equation of motion 
dx(1,1)=x(2);
dx(2,1)=1/(M+m-m*cos(x(3))^2)*(m*l*x(4)^2*sin(x(3))-m*g*sin(2*x(3))/2-k2*x(4)*cos(x(3))-k1*x(2)+F);
dx(3,1)=x(4);
dx(4,1)=1/(m*l*(M+m-m*cos(x(3))^2))*(-0.5*l*m^2*x(4)^2^sin(2*x(3))-m*cos(x(3))*(F-k1*x(2))+(M+m)*m*g*sin(x(3))-(M+m)*k2*x(4));
end

%

[Walter Roberson]

Are you encountering an error message? If not then what should we be looking at to be able to tell that there is a problem or not?