Calculus is at the core of nearly every branch of science: computer science, physics, engineering, business, medicine, statistics, economics, and more. It allows you to find optimal solutions in complex or changing systems. In physics, calculus forms the basis for everything from electromagnetism to classical mechanics. In finance, the concepts of stochastic calculus and Brownian motion help you to understand fluctuating asset prices. In medicine, calculus is used to compute the ideal angle for a branching blood vessel, allowing doctors to maximize flow. Calculus is also at the core of many software programs performing backend calculations for a wide range of applications. Astronauts and aerospace engineers, for example, use calculus to model the flight trajectories and aerodynamics of air and space vessels.