Math Problem Statement

Express the function graphed on the axes below as a piecewise function.

Express the function graphed on the axes below as a piecewise function.

Solution

The graph shows two line segments, each with different slopes and defined over different intervals for xx. To express this as a piecewise function, we need to:

  1. Find the equations of the two lines.
  2. Determine the domain for each line segment.

Left Line Segment:

  • This line goes through points (9,9)(-9, 9) and (4,4)(-4, -4).

  • To find the slope mm of the line: m=y2y1x2x1=494(9)=135m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{-4 - 9}{-4 - (-9)} = \frac{-13}{5} So, the slope is m=135m = -\frac{13}{5}.

  • Now, using the point-slope form of the equation yy1=m(xx1)y - y_1 = m(x - x_1), and taking (4,4)(-4, -4): y+4=135(x+4)y + 4 = -\frac{13}{5}(x + 4) Expanding this: y=135x5254=135x725y = -\frac{13}{5}x - \frac{52}{5} - 4 = -\frac{13}{5}x - \frac{72}{5} The equation of the left line segment is: y=135x725for9x4y = -\frac{13}{5}x - \frac{72}{5} \quad \text{for} \quad -9 \leq x \leq -4

Right Line Segment:

  • This line goes through points (7,6)(7, -6) and (9,9)(9, -9).

  • The slope mm of the line is: m=9(6)97=32m = \frac{-9 - (-6)}{9 - 7} = \frac{-3}{2} So, the slope is m=32m = -\frac{3}{2}.

  • Again, using the point-slope form, and taking (7,6)(7, -6): y+6=32(x7)y + 6 = -\frac{3}{2}(x - 7) Expanding this: y=32x+2126=32x+212122=32x+92y = -\frac{3}{2}x + \frac{21}{2} - 6 = -\frac{3}{2}x + \frac{21}{2} - \frac{12}{2} = -\frac{3}{2}x + \frac{9}{2} The equation of the right line segment is: y=32x+92for7x9y = -\frac{3}{2}x + \frac{9}{2} \quad \text{for} \quad 7 \leq x \leq 9

Final Piecewise Function:

Thus, the piecewise function for the graph is:

\begin{cases} -\frac{13}{5}x - \frac{72}{5} & \text{for} \quad -9 \leq x \leq -4 \\ -\frac{3}{2}x + \frac{9}{2} & \text{for} \quad 7 \leq x \leq 9 \end{cases}$$ Do you need further details or have any questions about this? Here are 5 related questions to explore: 1. How can you verify the points on each segment to ensure they satisfy the equations found? 2. What are the slopes and intercepts telling us about the rate of change of each line? 3. How would the piecewise function change if the domain of each segment were extended? 4. Can you express the piecewise function differently using inequalities or in different notations? 5. How do the discontinuities in the graph affect the overall function? **Tip:** To solve piecewise functions, always focus on the endpoints of each domain and confirm the function behaves as expected at those points.

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Math Problem Analysis

Mathematical Concepts

Algebra
Piecewise Functions
Linear Equations

Formulas

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

Theorems

Linear equation properties

Suitable Grade Level

Grades 9-12