math

Piecewise Functions
  • Definition: A piecewise function is a function that is defined by multiple sub-functions, each of which applies to a certain interval of the independent variable.
  • General Form:
    f(x) = \begin{cases}
    f1(x) & \text{if } x < a \ f2(x) & \text{if } a \leq x < b \
    f_3(x) & \text{if } x \geq b
    \end{cases}
  • Example:
    f(x) = \begin{cases}
    x^2 & \text{if } x < 0 \
    2x + 1 & \text{if } 0 \leq x < 3 \
    5 & \text{if } x \geq 3
    \end{cases}
  • Graphing:
    • Graph each piece separately and ensure to use open or closed circles to denote whether the endpoints are included in each interval.
Linear Functions
  • Definition: A linear function is a function that can be expressed in the form of f(x)=mx+bf(x) = mx + b, where mm represents the slope and bb the y-intercept.
  • Slope (m): The slope of a line indicates its steepness and direction. It is calculated as:
    m=y<em>2−y</em>1x<em>2−x</em>1m = \frac{y<em>2 - y</em>1}{x<em>2 - x</em>1}
  • Y-Intercept (b): The y-intercept is where the line crosses the y-axis (i.e., when x=0x = 0).
  • Graphing:
    • Start at the y-intercept (b) on the y-axis.
    • From there, use the slope (m) to find other points on the line. For example, if the slope is 22, rise 2 units up and run 1 unit to the right to find another point.
Key Differences
  • Form: Piecewise functions can contain multiple definitions based on the value of x, whereas linear functions maintain a constant slope throughout their domain.
  • Graph Shape: Piecewise functions can appear broken or segmented due to their multiple definitions, while linear functions produce straight lines.
Important Concepts
  • Continuity: Check for continuity at the boundaries in piecewise functions.
  • Domain and Range: Identify the domain and range for both piecewise and linear functions.