Representation Examples in Math

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Representation.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Math.

Concept Recap

A way of encoding or expressing mathematical ideas using symbols, diagrams, or other forms.

The same idea can be shown in multiple waysβ€”each reveals different aspects.

Read the full concept explanation β†’

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Changing representation often makes problems easier or harder.

Common stuck point: The representation is not the object itself β€” a graph of f(x) is a picture of the function, not the function; changing representation does not change the underlying math.

Sense of Study hint: Try expressing the same idea in at least two forms: a formula, a picture, a table, or words. Whichever form makes the answer obvious is the right one.

Worked Examples

Example 1

easy
Represent the set A = \{1,2,3,4,5,6,7,8,9,10\} with B = \{2,4,6,8,10\} and C = \{1,3,5\} using three different representations: (1) roster notation, (2) set-builder notation, (3) a Venn diagram description.

Solution

  1. 1
    Roster: A=\{1,2,\ldots,10\}, B=\{2,4,6,8,10\}, C=\{1,3,5\}.
  2. 2
    Set-builder: B=\{x \in A : x \text{ is even}\}, C=\{x \in A : x \text{ is odd and } x \le 5\}.
  3. 3
    Venn diagram: Draw a rectangle for A. Inside, draw circle B (even numbers) and circle C (odd \le 5). They do not overlap. Elements 7,9 are in A but outside both circles.

Answer

B = \{x \in A : 2 \mid x\},\quad C = \{x \in A : x \text{ odd},\; x \le 5\}
The same mathematical object can be described in multiple ways. Switching representations often reveals different aspects of the structure and is a key problem-solving skill.

Example 2

medium
The inequality |x - 3| < 2 can be represented as an absolute value inequality, a compound inequality, and an interval. Convert between all three.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Write the solution set of x^2 = 9 in (a) roster notation, (b) set-builder notation.

Example 2

medium
A function f triples its input. Represent f as (a) a formula, (b) a table for inputs \{1,2,3,4\}, (c) a verbal description.