This document contains a worksheet with problems involving differential equations. It asks the student to: 1) Compute the general solutions to three differential equations. 2) Apply Picard-Lindelöf theorem to verify existence and uniqueness of solutions for an initial value problem, and compute Picard iterates to approximate the solution. 3) Analyze an equation involving trigonometric functions by studying equilibrium points and stability. 4) Prove that autonomous differential equations cannot have periodic solutions.