Math Problem Statement

For each of the following functions f(x) = 5^x and g(x) = 3x^3, complete the table for integer values of x between 0 and 5. Then sketch both functions on the same grid and determine if one function eventually dominates. If so, state which function and at approximately what value of x.

Solution

Let's work through this problem step by step.

Part (a): Completing the Table

For the given functions:

  • f(x)=5xf(x) = 5^x
  • g(x)=3x3g(x) = 3x^3

We'll calculate each function's values for integer values of xx from 0 to 5.

Calculations:

  1. When x=0x = 0:

    • f(0)=50=1f(0) = 5^0 = 1
    • g(0)=3×03=0g(0) = 3 \times 0^3 = 0
  2. When x=1x = 1:

    • f(1)=51=5f(1) = 5^1 = 5
    • g(1)=3×13=3g(1) = 3 \times 1^3 = 3
  3. When x=2x = 2:

    • f(2)=52=25f(2) = 5^2 = 25
    • g(2)=3×23=3×8=24g(2) = 3 \times 2^3 = 3 \times 8 = 24
  4. When x=3x = 3:

    • f(3)=53=125f(3) = 5^3 = 125
    • g(3)=3×33=3×27=81g(3) = 3 \times 3^3 = 3 \times 27 = 81
  5. When x=4x = 4:

    • f(4)=54=625f(4) = 5^4 = 625
    • g(4)=3×43=3×64=192g(4) = 3 \times 4^3 = 3 \times 64 = 192
  6. When x=5x = 5:

    • f(5)=55=3125f(5) = 5^5 = 3125
    • g(5)=3×53=3×125=375g(5) = 3 \times 5^3 = 3 \times 125 = 375

Table Completion:

xxf(x)f(x)g(x)g(x)
010
153
22524
312581
4625192
53125375

Part (b): Sketching Both Functions

  • To sketch these functions, you would plot the points obtained from the table for f(x)f(x) and g(x)g(x).
  • Notice that f(x)=5xf(x) = 5^x grows exponentially, while g(x)=3x3g(x) = 3x^3 grows polynomially.
  • Initially, g(x)g(x) is close to or even larger than f(x)f(x) for smaller values of xx, but as xx increases, f(x)f(x) grows much faster due to the nature of exponential functions.

Part (c): Dominance of One Function

Exponential functions grow faster than polynomial functions for large values of xx. Thus, f(x)f(x) will eventually dominate g(x)g(x).

  • Observing the table, f(x)f(x) begins to dominate g(x)g(x) starting from x=3x = 3 and beyond.

So, the answer for (c) would be:

  • f(x)f(x) dominates over the interval (3,)(3, \infty).

Would you like more details on any step, or do you have specific questions?


Here are some related questions to deepen your understanding:

  1. Why does an exponential function eventually grow faster than a polynomial function?
  2. How would the table values change if the base of f(x)f(x) was smaller, such as f(x)=2xf(x) = 2^x?
  3. What happens to the dominance interval if g(x)g(x) had a higher degree, say g(x)=3x4g(x) = 3x^4?
  4. Can you find a general rule for when an exponential function dominates a polynomial function?
  5. How would the answers change if g(x)g(x) was a logarithmic function, like g(x)=ln(x)g(x) = \ln(x)?

Tip: Exponential functions of the form axa^x, where a>1a > 1, grow faster than any polynomial function as xx approaches infinity.

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Math Problem Analysis

Mathematical Concepts

Exponential functions
Polynomial functions
Function dominance

Formulas

f(x) = 5^x
g(x) = 3x^3

Theorems

Exponential growth vs polynomial growth

Suitable Grade Level

Grades 10-12