Math Problem Statement

All exponential functions can be written in many forms. Write the function f, of, t, equals, 41000, left parenthesis, one half, right parenthesis, start superscript, start fraction, t, divided by, 8, end fraction, end superscriptf(t)=41000( 2 1 ​ ) 8 t ​

in the form f, of, t, equals, a, b, start superscript, start fraction, t, divided by, 15, end fraction, end superscriptf(t)=ab 15 t ​

. Round all coefficients to four decimal places.

Solution

The given exponential function is:

f(t)=41000(12)t8f(t) = 41000 \left( \frac{1}{2} \right)^{\frac{t}{8}}

We need to rewrite it in the form:

f(t)=abt15f(t) = a \cdot b^{\frac{t}{15}}

Step-by-step process:

  1. Compare the given form with the desired form: The desired form has an exponent of t15\frac{t}{15}, but the original function has t8\frac{t}{8} as the exponent base.

  2. Rewrite the base: To match the two forms, we need to manipulate the exponent. The current exponent is t8\frac{t}{8}, so we need to adjust this to be t15\frac{t}{15}.

    Start with the base of the exponential function: (12)t8=((12)18)t\left( \frac{1}{2} \right)^{\frac{t}{8}} = \left( \left( \frac{1}{2} \right)^{\frac{1}{8}} \right)^t

  3. Adjust the base to match the desired exponent: We need to express this as bt15b^{\frac{t}{15}}. To do so, we need: (12)18=b115\left( \frac{1}{2} \right)^{\frac{1}{8}} = b^{\frac{1}{15}} To find bb, we raise both sides to the power of 15: b=(12)158b = \left( \frac{1}{2} \right)^{\frac{15}{8}}

  4. Calculate bb: Now, calculate (12)158\left( \frac{1}{2} \right)^{\frac{15}{8}}: b=(12)1.875=0.1240(rounded to four decimal places)b = \left( \frac{1}{2} \right)^{1.875} = 0.1240 \quad (\text{rounded to four decimal places})

  5. Adjust aa: Now that we have the new base bb, we need to adjust the constant coefficient aa. To do this, we recognize that:

    f(t)=41000(12)t8=abt15f(t) = 41000 \cdot \left( \frac{1}{2} \right)^{\frac{t}{8}} = a \cdot b^{\frac{t}{15}}

    So, aa is: a=41000bt15=41000bt15a = 41000 \cdot b^{-\frac{t}{15}} = \frac{41000}{b^{\frac{t}{15}}}

    Since bt15=(12)t15b^{\frac{t}{15}} = \left( \frac{1}{2} \right)^{\frac{t}{15}}, we use the relation and calculate it:

    a=41000(0.1240)1=410008.0645330645.8000a = 41000 \cdot (0.1240)^{-1} = 41000 \cdot 8.0645 \approx 330645.8000

Final Answer:

The function in the desired form is:

f(t)=330645.80000.1240t15f(t) = 330645.8000 \cdot 0.1240^{\frac{t}{15}}

Would you like a more detailed breakdown or help with another question? Here's a tip: Exponential functions are powerful for modeling growth and decay, and converting between different forms can be useful for easier interpretation of data.

Related Questions:

  1. How do you determine the growth or decay rate from an exponential function?
  2. What is the impact of changing the exponent in an exponential function?
  3. How can you use logarithms to solve for unknowns in exponential equations?
  4. How do you graph exponential functions and what do their graphs look like?
  5. What is the significance of the base in an exponential function?

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Function Manipulation
Exponents
Base Conversion

Formulas

f(t) = a * b^(t/k)
b = (1/2)^(15/8)

Theorems

Exponential Function Conversion

Suitable Grade Level

Grades 9-11