Math Problem Statement

If f, of, xf(x) is an exponential function of the form of y, equals, a, b, to the power xy=ab x where f, of, minus, 5, equals, 11f(−5)=11 and f, of, 0, equals, 30f(0)=30, then find the value of f, of, minus, 3, point, 5f(−3.5), to the nearest hundredth.

Solution

We are given that the function f(x)f(x) is an exponential function of the form:

f(x)=abxf(x) = ab^x

Where aa and bb are constants, and we are provided with the following information:

  • f(5)=11f(-5) = 11
  • f(0)=30f(0) = 30

Step 1: Use f(0)=30f(0) = 30 to find aa

At x=0x = 0, the exponential function becomes: f(0)=ab0=af(0) = ab^0 = a Since f(0)=30f(0) = 30, we know: a=30a = 30

Step 2: Use f(5)=11f(-5) = 11 to find bb

Now substitute f(5)=11f(-5) = 11 and a=30a = 30 into the equation: f(5)=ab5=30b5=11f(-5) = ab^{-5} = 30b^{-5} = 11 Solve for bb: b5=1130b^{-5} = \frac{11}{30} b=(1130)15=(3011)15b = \left( \frac{11}{30} \right)^{-\frac{1}{5}} = \left( \frac{30}{11} \right)^{\frac{1}{5}}

Calculating bb: b1.219b \approx 1.219

Step 3: Find f(3.5)f(-3.5)

Now that we have a=30a = 30 and b1.219b \approx 1.219, we can find f(3.5)f(-3.5): f(3.5)=30(1.219)3.5f(-3.5) = 30 \cdot (1.219)^{-3.5}

Calculating this: f(3.5)30(0.8203)24.609f(-3.5) \approx 30 \cdot (0.8203) \approx 24.609

Thus, the value of f(3.5)f(-3.5) to the nearest hundredth is: 24.61\boxed{24.61}


Would you like more details or have any questions?

Here are five questions for further exploration:

  1. How do you derive the general form of an exponential function?
  2. What happens to f(x)f(x) as xx becomes very large in exponential functions?
  3. How would you graph f(x)=abxf(x) = ab^x?
  4. Can exponential functions have negative bases? Why or why not?
  5. What is the significance of the base bb in an exponential function?

Tip: In exponential functions, when b>1b > 1, the function grows, and when 0<b<10 < b < 1, the function decays.

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Algebra
Logarithms

Formulas

f(x) = ab^x
b = (f(-5)/a)^(-1/5)

Theorems

Properties of Exponential Functions
Laws of Exponents

Suitable Grade Level

Grades 9-11