Solving second order ODE simulating simple pendulum

Objective: %solution of ode close all clear all clc %input b=0.5; %damping coefficient. g=9.81; %accelaration due to gravity in m/s^2 l=1; % length of the pendulum in m m=1; %mass of the ball in kg, %initial condition theta_0=[0;3]; %time limit t_span=linspace(0,20,500); %solving ode [t,results]=ode45(@(t,theta) ode1_fun(t,theta,b,g,l,m),…