The difference between the response of the linear version of the pendulum equation

Consider the pendulum example 1.10.3 with length of 1 m an initial conditions of θ0 =π/10 rad and ý θ 0 = 0. compare the difference between the response of the linear version of the pendulum equation (i.e. with sin(θ) = θ) and the response of the nonlinear version of the pendulum equation by plotting the response of both for four periods. (I need proper and full answer with mathcad code and no plagiarism)