Week 3 - Solving second order ODEs

clear all
close all
clc

%input value for odr damping, gravity, length, mass
b = 0.10
g = 9.81
l = 1
m = 0.1

%inital condition (theta = time&displacment)

theta_0 = [0;5]
t_span = linspace(0,10,500)

%solving the 2ed order ode

[t,result]= ode45(@(t,theta)ode_func(t,theta,b,g,l,m),t_span,theta_0)

function [dtheta_dt]=ode_func(t,theta,b,g,l,m)
theta1 = theta(1)
theta2 = theta(2)

dtheta1_dt = theta2
dtheta2_dt =-(b/l)*theta2-(g/l)*sin(theta1)

dtheta_dt = [dtheta1_dt; dtheta2_dt]
end

%plotting
hold on
plot(t,result(:,1))
hold on
plot(t,result(:,2))
xlabel('time')
ylabel('displacement')

ode result

https://drive.google.com/file/d/1wQ425VYzYBmAeIbSqqLvp84eLPWzy4Hm/view?usp=sharing