This document contains code to solve a differential equation and plot a function. It solves the differential equation 'Dy+y-4*cos(2*t)' with initial condition 'y(0)=1' for variable 't'. It then plots the function '(4*cos(2*t))/5 + 1/(5*exp(t)) + (8*sin(2*t))/5' from -5 to 5. The document was prepared by Jesus Tapia.