% Program 5.2
% Compound pendulum
% Dynamics 
% Newton-Euler equation of motion
% the program uses the function: R(t,x) 
% the function is defined in the program R.m

clear; clc; close; 

tfinal=10;
time=[0 tfinal];
x0=[pi/4 0]; %  x(1)(0)=pi/4  x(2)(0)=0 

% solve a second order ODE using MATLAB ODE45 function

[t,x]=ode45(@R,time,x0);

subplot(3,1,1),...
plot(t,x(:,1),'r'),xlabel('t'),ylabel('\theta'),grid,...
subplot(3,1,2),...
plot(t,x(:,2)),xlabel('t'),ylabel('\omega'),grid,...
subplot(3,1,3),...
plot(x(:,1),x(:,2)), xlabel('\theta'), ylabel('\omega'),grid