Week 3 - Solving second order ODEs

close all 
clear all
clc
 
b=0.05;
g=9.81;
l=1;
m=0.1;
 
theta_0 = [0;5];
 
t_span = linspace(0,10,500);

[t,results]= ode45(@(t,theta) odefunc(t,theta,b,g,l,m),t_span,theta_0 );
 
 
hold on 
plot(t,results(:,1))
plot(t,results(:,2))
legend('distance','velocity')



function [d_dt] = odefunc(t,theta,b,g,l,m)
theta1=theta(1);
theta2=theta(2);
dtheta1_dt=theta2;
dtheta2_dt= -(b/m)*theta2-(g/l)*sin(theta1);
d_dt=[dtheta1_dt;dtheta2_dt];
end