Week 3 - Solving second order ODEs

"INSERT SAMPLE CODE"

clear all
close all
clc

b=0.05;
g=9.81
l=1
m=1

% initial condition
theta_0 = [0;3];

%time points
t_span = linspace(0,20,300)

%solve ODE
[t, results] = ode45(@(t,theta) ode_func(t,theta,b,g,l,m),t_span,theta_0)

plot(t,results(:,1))
hold on
plot(t,results(:,2))
ylabel('plot')
xlabel('time')

Function:

function [dtheta_dt] = ode_func(t,theta,b,g,l,m)

theta1 = theta(1)
theta2 = theta(2)
dtheta1_dt = theta2;
dtheta2_dt = -(b/m)*theta2 - (g/l)*sin(theta1);
dtheta_dt = [dtheta1_dt; dtheta2_dt];
end