Introduction to Analysis

An introductory course that explores the fundamental concepts and techniques of mathematical analysis.

Basic Concepts

Functions and Continuity

What Is a Function?

A function connects every input from one set (like real numbers) to exactly one output in another set. Think of it as a math machine: put in a number, get out a number!

Continuity: No Surprises!

A function is continuous at a point if its output doesn't suddenly jump or break there. You can draw its graph without lifting your pencil.

The Formal Idea

A function \( f \) is continuous at \( x = a \) if: \[ \lim_{x \to a} f(x) = f(a) \] This means the value you get by plugging in numbers close to \( a \) is the same as just plugging in \( a \).

Why Is Continuity Important?

Continuous functions model real-world processes smoothly, like the growth of a plant or the change in temperature over time.

Real-World Analogy

Imagine walking along a path. If the path is continuous, you never have to jump over holes!

Examples

  • The function \( f(x) = x^2 \) is continuous everywhere.

  • The function \( f(x) = \frac{1}{x} \) is not continuous at \( x = 0 \), because you can't divide by zero.

In a Nutshell

Functions assign each input to an output, and continuity means their graphs are smooth with no jumps.