Solving second order ODEs

Objective: clear all close all clc g = 9.81; l = 1; m = 1; k=0.5 % Initial Conditions theta_0 = [0;4]; % Time t_span = linspace(0,25,500); % Solving ODE [t, results] = ode45(@(t,theta)secondode(t,theta,k,g,l,m),t_span,theta_0); figure(1) plot(t,results(:,1)) hold on plot(t,results(:,2),\'red\') ylabel(\'Responses\') xlabel(\'T\')…