Differential calculus is a branch of mathematics that focuses on how things change. It helps us understand the concept of a derivative, which measures the rate at which a quantity changes. For example, if you want to know how fast a car is moving at a specific moment, differential calculus can provide that information by analyzing the car's position over time. In practical terms, differential calculus is used in various fields, such as physics, engineering, and economics. It allows us to solve problems involving motion, optimize functions, and model real-world situations. By studying the slopes of curves, we can gain insights into trends and behaviors in different scenarios.