Math Problem Statement

The graph of a piecewise function, f(x), is depicted above. Find its equation.

Solution

The graph shows a piecewise function, f(x)f(x), made up of three distinct line segments. To find the equation of each segment, we will determine the slope and y-intercept for each part.

Identifying the intervals and finding the equations:

  1. First segment (Leftmost horizontal line):

    • This segment is horizontal and exists from x=x = -\infty to x=8x = -8.
    • The line is constant at y=10y = -10 (no slope), so the equation is: f(x)=10forx8f(x) = -10 \quad \text{for} \quad x \leq -8
  2. Second segment (Middle line):

    • This segment starts at (8,10)(-8, -10) and ends at (1,5)(1, 5).
    • To find the slope (mm): m=5(10)1(8)=159=53m = \frac{5 - (-10)}{1 - (-8)} = \frac{15}{9} = \frac{5}{3}
    • Using the point-slope form yy1=m(xx1)y - y_1 = m(x - x_1) with (x1,y1)=(8,10)(x_1, y_1) = (-8, -10): y+10=53(x+8)y + 10 = \frac{5}{3}(x + 8) Expanding: y=53x+53(8)10=53x+40310=53x+403303=53x+103y = \frac{5}{3}x + \frac{5}{3}(8) - 10 = \frac{5}{3}x + \frac{40}{3} - 10 = \frac{5}{3}x + \frac{40}{3} - \frac{30}{3} = \frac{5}{3}x + \frac{10}{3} So, the equation for this segment is: f(x)=53x+103for8<x1f(x) = \frac{5}{3}x + \frac{10}{3} \quad \text{for} \quad -8 < x \leq 1
  3. Third segment (Rightmost line):

    • This segment starts at (1,5)(1, 5) and continues upwards.
    • Using points (1,5)(1, 5) and (7,13)(7, 13) to find the slope: m=13571=86=43m = \frac{13 - 5}{7 - 1} = \frac{8}{6} = \frac{4}{3}
    • Using point-slope form yy1=m(xx1)y - y_1 = m(x - x_1) with (x1,y1)=(1,5)(x_1, y_1) = (1, 5): y5=43(x1)y - 5 = \frac{4}{3}(x - 1) Expanding: y=43x43+5=43x+113y = \frac{4}{3}x - \frac{4}{3} + 5 = \frac{4}{3}x + \frac{11}{3} So, the equation for this segment is: f(x)=43x+113forx>1f(x) = \frac{4}{3}x + \frac{11}{3} \quad \text{for} \quad x > 1

Piecewise Function:

\begin{cases} -10 & \text{for} \quad x \leq -8 \\ \frac{5}{3}x + \frac{10}{3} & \text{for} \quad -8 < x \leq 1 \\ \frac{4}{3}x + \frac{11}{3} & \text{for} \quad x > 1 \end{cases}$$ Let me know if you'd like more details or have any questions! ### 5 Related Questions: 1. How do you derive the equation of a line given two points? 2. What are the key characteristics of piecewise functions? 3. How do you determine the continuity of a piecewise function? 4. Can a piecewise function have discontinuities? 5. How do you evaluate limits for piecewise functions at boundary points? ### Tip: When working with piecewise functions, always carefully check the boundaries of each piece to ensure correct application of the function's domain.

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Math Problem Analysis

Mathematical Concepts

Piecewise Functions
Linear Equations
Slope-Intercept Form
Point-Slope Form

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Slope-intercept form: y = mx + b
Point-slope form: y - y1 = m(x - x1)

Theorems

Linear equation properties
Piecewise function definition

Suitable Grade Level

Grades 10-12