Math Problem Statement

Graph the exponential function f(x)=3/2⋅(4/3)^x −1

Use the following to help you plot the function.

When x=1 , f(x)=

1

The y-intercept of the function is
1/2

The horizontal asymptote of the exponential function is at y=

-1

(To graph an exponential function, plot two points on the graph, and then select any point on the horizontal asymptote)

Solution

To graph the function f(x)=32(43)x1f(x) = \frac{3}{2} \cdot \left( \frac{4}{3} \right)^x - 1, we can proceed as follows:


Key Information:

  1. Given Point: x=1,f(x)=1x = 1, f(x) = 1
  2. Y-intercept: f(0)=12f(0) = \frac{1}{2}
  3. Horizontal Asymptote: y=1y = -1

Steps to Plot the Function:

  1. Y-Intercept at x=0x = 0:
    Substituting x=0x = 0 into the function:
    f(0)=32(43)01=3211=321=12f(0) = \frac{3}{2} \cdot \left( \frac{4}{3} \right)^0 - 1 = \frac{3}{2} \cdot 1 - 1 = \frac{3}{2} - 1 = \frac{1}{2}
    Thus, the y-intercept is (0,12)\left( 0, \frac{1}{2} \right).

  2. Point at x=1x = 1:
    It is given that f(1)=1f(1) = 1, so the point (1,1)(1, 1) is on the graph.

  3. Horizontal Asymptote:
    The function f(x)=32(43)x1f(x) = \frac{3}{2} \cdot \left( \frac{4}{3} \right)^x - 1 has a horizontal asymptote at y=1y = -1.
    This happens because the exponential term approaches 0 as xx \to -\infty, leaving the constant 1-1 as the limiting value.

  4. General Behavior of the Function:

    • The base 43>1\frac{4}{3} > 1, so the exponential function grows as xx increases.
    • As xx \to -\infty, the function approaches the horizontal asymptote y=1y = -1.

Plotting Points:

  • (0,12)(0, \frac{1}{2}) → y-intercept
  • (1,1)(1, 1) → another given point
  • Horizontal asymptote: y=1y = -1.

Sketch:

  1. Start with the horizontal asymptote y=1y = -1. Draw this as a dashed horizontal line.
  2. Plot the points (0,12)(0, \frac{1}{2}) and (1,1)(1, 1).
  3. Since the function grows exponentially, the curve will increase as xx \to \infty and approach y=1y = -1 as xx \to -\infty.

Final Graph Description:

The graph starts close to y=1y = -1 on the far left and increases through the points (0,12)(0, \frac{1}{2}) and (1,1)(1, 1). It continues to grow exponentially as xx \to \infty.

Would you like me to provide a visual graph of this function? Let me know if you need further explanations or calculations!


Related Questions:

  1. What happens to the function if the base 43\frac{4}{3} is replaced with 22?
  2. How does the horizontal asymptote change if we replace 1-1 with another constant?
  3. What is the behavior of the function as xx \to -\infty?
  4. How do you determine the y-intercept of any exponential function?
  5. Can you rewrite the function in terms of a transformation of y=axy = a^x?

Tip:

The y-intercept of an exponential function f(x)=abx+cf(x) = a \cdot b^x + c can always be found by substituting x=0x = 0.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Graphing
Horizontal Asymptotes

Formulas

f(x) = a ⋅ b^x + c
y-intercept is found by substituting x = 0

Theorems

Properties of Exponential Functions
Horizontal Asymptote Behavior of Exponential Functions

Suitable Grade Level

Grades 9-12