Calculus is a branch of mathematics that deals with the study of rates of change and how things change over time. It is divided into two main branches: differential calculus and integral calculus.

Differential calculus deals with the study of rates of change and slopes of curves. It involves finding the derivative of a function, which is the rate of change of the function at a particular point. The derivative is used to find the slope of a curve at a particular point, which can be used to solve problems in physics, engineering, and economics.

Integral calculus deals with the study of areas and volumes. It involves finding the integral of a function, which is the area under the curve of the function. The integral is used to find the total area or volume of a shape, which can be used to solve problems in physics, engineering, and economics.

Calculus is used in many fields, including physics, engineering, economics, and computer science. It is also used in everyday life, such as in calculating the speed of a car, the rate of change of a stock price, or the amount of medication needed for a patient.

Some of the key concepts in calculus include limits, derivatives, integrals, and differential equations. These concepts are used to solve problems in a wide range of fields and are essential for understanding many advanced mathematical concepts.