Math Problem Statement

The graph shows a transformation of y = 2^x. Write an equation of the form y = A · 2^x + k for the graph.

Solution

The given graph is a transformation of the exponential function y=2xy = 2^x, and you are tasked with writing an equation of the form y=A2x+ky = A \cdot 2^x + k.

Let's analyze the graph:

  1. Reflection: The graph is a reflection of y=2xy = 2^x over the x-axis because the curve slopes downward as xx increases. This indicates that the coefficient AA is negative.

  2. Vertical Shift: The graph appears to be shifted downward. The horizontal asymptote of the original function y=2xy = 2^x is at y=0y = 0, but for this graph, the asymptote is at y=3y = -3. Therefore, the vertical shift kk is 3-3.

  3. Equation form: The reflection and vertical shift suggest the equation will take the form: y=A2x3y = -A \cdot 2^x - 3 where AA is positive.

To determine AA, we use a point on the graph. Let's take the point (0,1)(0, -1), which lies on the graph.

Substitute x=0x = 0 and y=1y = -1 into the equation: 1=A203-1 = -A \cdot 2^0 - 3 1=A3-1 = -A - 3 Solve for AA: 1+3=A-1 + 3 = -A A=2A = 2

Thus, the equation of the graph is: y=22x3y = -2 \cdot 2^x - 3

Final Answer:

y=22x3y = -2 \cdot 2^x - 3

Would you like further clarification or details?

Here are 5 related questions you could explore:

  1. How does the transformation change if kk is positive?
  2. What if the reflection was over the y-axis instead of the x-axis?
  3. How would a horizontal shift affect the equation?
  4. What would the graph look like if AA were a fraction?
  5. How does the base of the exponential function (e.g., using 3 instead of 2) affect the transformation?

Tip: To identify reflections, check whether the graph is flipped relative to the original function about an axis.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Transformations
Reflections
Vertical Shifts

Formulas

y = A · 2^x + k
Exponential Function Equation
Reflections over x-axis

Theorems

Exponential Growth and Decay

Suitable Grade Level

Grades 9-12