Chapter 1
Linear Equations and Graphing
Course: Gre
Subject: Gre Quantitative Reasoning
Chapter: Quadratic Equations And Polynomials
Introduction: Functions as Everyday Tools
Functions are not merely abstract mathematical concepts confined to textbooks. They appear constantly in daily life. The amount paid at a gas station depends on the gallons pumped. The profit a bakery earns depends on the number of pastries sold. The distance walked in an hour depends on the number of steps taken. Each of these relationships can be expressed as a function.
A function describes the relationship between an independent variable (input) and a dependent variable (output) in which each input produces exactly one output.
Variables in a Function
Functions involve two types of variables:
| Variable Type | Role | Symbol | | Independent variable | Input; can be chosen freely | Often x | | Dependent variable | Output; depends on the input | Often yor f(x) |