Math Problem Statement

The graph of a semi-log plot of an exponential function of the form h(x) = ab^x passes through the coordinates (0, 0.4) and (4, 5). The x-axis has linear scaling, and the y-axis has a logarithmic base 10 scale. What are the values of a and b in the exponential function?

Solution

The image shows a problem related to the exponential function in a semi-logarithmic plot. The function is of the form h(x)=abxh(x) = ab^x, where the graph passes through the coordinates (0,0.4)(0, 0.4) and (4,5)(4, 5). The task is to determine the values of aa and bb in the exponential function, given that the x-axis has linear scaling and the y-axis has a logarithmic scale with base 10.

Let's go step-by-step to solve for aa and bb:

  1. General form of the exponential function: The equation is given as: h(x)=abxh(x) = ab^x

  2. Substitute the given points into the equation:

    • For the point (0,0.4)(0, 0.4), substitute x=0x = 0 and h(0)=0.4h(0) = 0.4: 0.4=ab0(since anything raised to the power of 0 is 1)0.4 = ab^0 \quad \text{(since anything raised to the power of 0 is 1)} 0.4=a0.4 = a So, a=0.4a = 0.4.
  3. Substitute the second point (4,5)(4, 5):

    • For the point (4,5)(4, 5), substitute x=4x = 4 and h(4)=5h(4) = 5 into the equation: 5=0.4b45 = 0.4b^4 Solve for bb: b4=50.4=12.5b^4 = \frac{5}{0.4} = 12.5 b=12.541.861b = \sqrt[4]{12.5} \approx 1.861

Thus, the values of aa and bb are:

  • a=0.4a = 0.4
  • b1.861b \approx 1.861

Let me know if you'd like further clarification or help with other related problems!


Related questions to explore:

  1. How do logarithmic plots help in interpreting exponential functions?
  2. What are the different forms of exponential functions used in mathematical modeling?
  3. How does changing the base bb in an exponential function affect its growth rate?
  4. Can exponential functions be applied in real-world scenarios, like population growth or finance?
  5. How do you solve for parameters in exponential equations with other points on the curve?

Tip: When working with exponential equations, remember that logarithmic transformations can help linearize the data, making it easier to find the parameters.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Logarithmic Scaling
Algebra

Formulas

h(x) = ab^x

Theorems

Exponential equation behavior
Logarithmic transformation

Suitable Grade Level

Grades 9-11