# Precalculus

College calculus has many similarities to high school calculus, but the mathematics is typically much more rigorously introduced.

## Real and complex numbers

A complex number is an element of a number system that extends the real numbers with a specific element denoted i, called the imaginary unit and satisfying the equation i² = −1; every complex number can be expressed in the form a + bi, where a and b are real numbers

## Functions

A function from a set X to a set Y assigns to each element of X exactly one element of Y. The set X is called the domain of the function and the set Y is called the codomain of the function.

## Polynomials

A polynomial is defined as an expression which is composed of variables, constants and exponents, that are combined using mathematical operations such as addition, subtraction, multiplication and division

## Trigonometry

The study of angles and of the angular relationships of planar and three-dimensional figures is known as trigonometry. The trigonometric functions (also called the circular functions) comprising trigonometry are the cosecant ,cosine , cotangent , secant , sine , and tangent

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