What is an Integral?

UNDERSTANDING INTEGRALS

An integral is used to deal with infinitesimally small quantities and their summation to a final value that we are seeking. Integrals can be divided into two main categories: indefinite integrals and definite integrals.

WHAT IS AN INTEGRAL?

At its most basic level, an integral can be understood as a process by which we calculate the total value or "sum" of something that is changing. An integral allows us to calculate, for example, the total area under a curve on a graph or the total distance traveled if the speed is constantly changing.

TWO MAIN TYPES OF INTEGRALS:

• INDEFINITE INTEGRAL: This is the basic form of an integral, which gives us a function (or a family of functions, due to the constant of integration). The indefinite integral of a function tells us what the original function (antiderivative) must have been before it was differentiated. We write it as ∫f(x) dx, where f(x) is the function we are integrating, and dx represents the variable of integration. The result is F(x) + C, where F(x) is an antiderivative of f(x).
• DEFINITE INTEGRAL: This type of integral gives us a numerical value and is used to calculate areas, volumes, or other quantities. It is written with an upper and lower limit, for example, ∫ from a to b of f(x) dx (often denoted as ∫[a, b] f(x) dx in the text), where 'a' and 'b' are the limits of the interval over which we integrate the function f(x).

CALCULATING INTEGRALS

Various techniques are used to calculate integrals.

• For indefinite integrals, it's about finding a function whose derivative is equal to the given expression (finding the antiderivative).
• For definite integrals, we often calculate the difference between the values of an antiderivative (the indefinite integral) at the upper and lower limits (this is a part of the Fundamental Theorem of Calculus).

APPLICATION OF INTEGRALS

Imagine you want to calculate the total distance a car travels if its speed is constantly changing. If the car's speed at a given time is represented by a function, we can use an integral to calculate the total distance traveled over a specific time period. (Specifically, integrating the velocity function with respect to time gives the displacement).

CONCLUSION

Integrals are a key part of mathematics that help us calculate how much space something occupies, for example, an area or a volume. They are very useful not only in school but also in science and engineering, as they help us solve various problems, from physics to computer science. Understanding integrals opens doors to a better comprehension of mathematics and the improvement of technologies we use every day.