Math Problem Statement

Writing Exponential Functions

Given the Initial Value and Rate of Change, write the exponential function for each of the following.

Initial ValueRateFunction

180

Growth Rate = 12%

f(x)=   

56

Growth Rate = 7%

f(x)=   

104

Growth Rate = 6.5%

f(x)=   

73

Growth Rate = 103%

f(x)=   

176

Decay Rate = 29%

f(x)=   

122

Decay Rate = 9%

f(x)=   

197

Decay Rate = 0.1%

f(x)=   

Solution

To write the exponential function, we use the general formula:

f(x)=a(1+r)xf(x) = a(1 + r)^x

where:

  • aa is the initial value,
  • rr is the rate of change (expressed as a decimal),
  • xx is the input variable (time or another independent variable).

For decay rates, rr will be negative, so the formula becomes:
f(x)=a(1r)xf(x) = a(1 - r)^x

Here are the solutions for the given values:

  1. Initial Value = 180, Growth Rate = 12%
    f(x)=180(1+0.12)x=180(1.12)xf(x) = 180(1 + 0.12)^x = 180(1.12)^x

  2. Initial Value = 56, Growth Rate = 7%
    f(x)=56(1+0.07)x=56(1.07)xf(x) = 56(1 + 0.07)^x = 56(1.07)^x

  3. Initial Value = 104, Growth Rate = 6.5%
    f(x)=104(1+0.065)x=104(1.065)xf(x) = 104(1 + 0.065)^x = 104(1.065)^x

  4. Initial Value = 73, Growth Rate = 103%
    f(x)=73(1+1.03)x=73(2.03)xf(x) = 73(1 + 1.03)^x = 73(2.03)^x

  5. Initial Value = 176, Decay Rate = 29%
    f(x)=176(10.29)x=176(0.71)xf(x) = 176(1 - 0.29)^x = 176(0.71)^x

  6. Initial Value = 122, Decay Rate = 9%
    f(x)=122(10.09)x=122(0.91)xf(x) = 122(1 - 0.09)^x = 122(0.91)^x

  7. Initial Value = 197, Decay Rate = 0.1%
    f(x)=197(10.001)x=197(0.999)xf(x) = 197(1 - 0.001)^x = 197(0.999)^x

Let me know if you’d like further clarification or a detailed explanation of how these formulas are derived!


Related Questions:

  1. What happens to the exponential function as xx \to \infty for growth and decay rates?
  2. How do you convert a percentage growth rate to a decimal form?
  3. What is the difference between linear and exponential growth?
  4. How would a negative initial value affect the exponential function?
  5. Can exponential functions model real-life situations? Provide examples.

Tip: Always ensure the rate is correctly expressed as a decimal (e.g., 12% = 0.12) when substituting into the formula

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Growth and Decay
Rate of Change

Formulas

f(x) = a(1 + r)^x for growth
f(x) = a(1 - r)^x for decay

Theorems

Exponential Growth and Decay Formula

Suitable Grade Level

Grades 9-12