Math Problem Statement

An exponential function f(x) = ab^x passes through the points (0, 4000) and (3, 1372). What are the values of a and b?

Solution

To solve the problem, we are given the exponential function f(x)=abxf(x) = ab^x, and it passes through the points (0,4000)(0, 4000) and (3,1372)(3, 1372). We need to find the values of aa and bb.

Step 1: Solve for aa using the point (0,4000)(0, 4000)

When x=0x = 0: f(0)=ab0=a1=af(0) = ab^0 = a \cdot 1 = a From the point (0,4000)(0, 4000), we know: a=4000a = 4000

Step 2: Substitute a=4000a = 4000 into the equation

The function becomes: f(x)=4000bxf(x) = 4000b^x

Step 3: Use the point (3,1372)(3, 1372) to solve for bb

When x=3x = 3, f(3)=1372f(3) = 1372: 1372=4000b31372 = 4000b^3 Divide through by 4000: b3=13724000b^3 = \frac{1372}{4000} b3=0.343b^3 = 0.343

Step 4: Solve for bb

Take the cube root of both sides: b=0.3433=0.7b = \sqrt[3]{0.343} = 0.7

Final Answers:

a=4000,b=0.7a = 4000, \quad b = 0.7

Let me know if you want detailed steps or further explanations!


Related Questions:

  1. How do we interpret the base bb in the context of exponential growth or decay?
  2. Can we find the equation of the exponential function after determining aa and bb?
  3. What would the function predict for x=5x = 5?
  4. How would the process differ for other types of functions, such as quadratic functions?
  5. What happens if one of the points lies at x=1x = 1? How does it simplify solving for bb?

Tip:

Always double-check your substitution into the function to ensure the given points are satisfied.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Solving Equations
Cube Roots

Formulas

f(x) = ab^x
b^n = x ↔ b = x^(1/n)

Theorems

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Suitable Grade Level

Grades 10-12