Math Problem Statement

Write an equation of the form y = A * 2^x + k for the given transformed graph.

Solution

To determine the equation of the form y=A2x+ky = A \cdot 2^x + k for the transformed graph, let’s analyze the graph step-by-step.

Step 1: Identify the transformations

  1. Reflection: The graph of y=2xy = 2^x usually increases as xx increases. Here, however, the graph decreases, suggesting a reflection across the x-axis. This means AA will be negative.
  2. Vertical Scaling: The curve seems stretched, suggesting AA might not just be -1.
  3. Vertical Shift: The graph does not appear to approach zero as xx \to -\infty, indicating a vertical shift. This will determine kk.

Step 2: Choose points to solve for AA and kk

From the graph:

  • At x=0x = 0, y=2y = 2.
  • At x=1x = 1, y=1y = -1.

Step 3: Set up equations based on these points

Using the general form y=A2x+ky = A \cdot 2^x + k:

  1. For x=0x = 0: 2=A20+k2=A+k2 = A \cdot 2^0 + k \Rightarrow 2 = A + k

  2. For x=1x = 1: 1=A21+k1=2A+k-1 = A \cdot 2^1 + k \Rightarrow -1 = 2A + k

Step 4: Solve the system of equations

From the first equation: k=2Ak = 2 - A

Substitute k=2Ak = 2 - A into the second equation: 1=2A+(2A)-1 = 2A + (2 - A) 1=A+2-1 = A + 2 A=3A = -3

Then substitute A=3A = -3 back into k=2Ak = 2 - A: k=2(3)=5k = 2 - (-3) = 5

Solution

The equation for the transformed graph is: y=32x+5y = -3 \cdot 2^x + 5

Would you like further explanation on any of these steps, or have additional questions?


Follow-up Questions

  1. What effect does changing the value of AA have on the graph?
  2. How does a vertical shift (the kk value) affect the asymptote of an exponential graph?
  3. How would the equation change if the graph were reflected over the y-axis instead?
  4. What transformations are needed to turn y=2xy = 2^x into y=42x7y = 4 \cdot 2^x - 7?
  5. How does the base of the exponent (here, 2) affect the steepness of the exponential curve?

Tip

When analyzing transformations, always check the reflection, scaling, and shifts in order; they each have a distinct impact on the shape and position of the graph.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Graph Transformations

Formulas

y = A * 2^x + k

Theorems

Transformation of Exponential Functions

Suitable Grade Level

Grades 9-11