Calculus has many applications in fields like engineering, science, biology, economics and other areas. It was initially developed for navigation but is now used in building skyscrapers, bridges, vehicles, studying ecosystems, measuring growth rates, astronomy, space technology, economics, business surveys, investment planning and more. The document provides examples of how differentiation and integration from calculus are applied in various disciplines like using it for robotics, electrical systems, drug concentration in biology, Newton's laws of motion, and economic concepts. It concludes by stating calculus is also employed in mapping, solving paradoxes, and other domains.