Math Problem Statement

Graph the exponential function, g(x)=(1/4)^x-2

Solution

To graph the exponential function:
g(x)=(14)x2g(x) = \left(\frac{1}{4}\right)^x - 2 we analyze its properties:

Step 1: Identify Key Features

  1. Base and Growth/Decay:

    • The base is 14\frac{1}{4}, which is a fraction between 0 and 1, meaning it represents exponential decay.
  2. Horizontal Asymptote:

    • The function has a horizontal asymptote at y=2y = -2 because of the vertical shift.
  3. Intercepts:

    • Y-Intercept: Set x=0x = 0: g(0)=(14)02=12=1g(0) = \left(\frac{1}{4}\right)^0 - 2 = 1 - 2 = -1 So, the y-intercept is (0,1)(0, -1).

    • X-Intercept: Set g(x)=0g(x) = 0 and solve for xx: (14)x2=0\left(\frac{1}{4}\right)^x - 2 = 0 (14)x=2\left(\frac{1}{4}\right)^x = 2 Take the logarithm on both sides: xlog(14)=log(2)x \log\left(\frac{1}{4}\right) = \log(2) Since log(1/4)=log(4)\log(1/4) = -\log(4), we get: x=log(2)log(4)x = \frac{\log(2)}{-\log(4)} x=log(2)2log(2)=12x = \frac{\log(2)}{-2\log(2)} = -\frac{1}{2} So, the x-intercept is (0.5,0)(-0.5, 0).

Step 2: Behavior of the Function

  • As xx \to \infty, g(x)2g(x) \to -2.
  • As xx \to -\infty, g(x)g(x) \to \infty.
  • The function is always decreasing.

Let's generate the graph now. numpy as np import matplotlib.pyplot as plt

Define the function g(x) = (1/4)^x - 2

def g(x): return (1/4)**x - 2

Generate x values

x_values = np.linspace(-3, 3, 400) y_values = g(x_values)

Plot the function

plt.figure(figsize=(8, 5)) plt.plot(x_values, y_values, label=r'$g(x) = \left(\frac{1}{4}\right)^x - 2$', color='blue')

Plot the asymptote y = -2

plt.axhline(y=-2, color='red', linestyle='dashed', label='Asymptote: $y=-2$')

Plot intercepts

plt.scatter([0], [-1], color='green', label='Y-Intercept (0,-1)') plt.scatter([-0.5], [0], color='purple', label='X-Intercept (-0.5,0)')

Labels and title

plt.xlabel('x') plt.ylabel('g(x)') plt.title('Graph of $g(x) = (1/4)^x - 2$') plt.axhline(0, color='black', linewidth=1) plt.axvline(0, color='black', linewidth=1) plt.legend() plt.grid()

Show the plot

plt.show()Here is the graph of g(x)=(14)x2g(x) = \left(\frac{1}{4}\right)^x - 2:

  • The red dashed line represents the horizontal asymptote at y=2y = -2.
  • The green point marks the y-intercept at (0,1)(0, -1).
  • The purple point marks the x-intercept at (0.5,0)(-0.5, 0).
  • The function decreases towards the asymptote as xx \to \infty and grows rapidly as xx \to -\infty.

Would you like more details or another transformation explained?

Related Questions:

  1. How does changing the base (e.g., 12\frac{1}{2} instead of 14\frac{1}{4}) affect the graph?
  2. What is the effect of shifting the function by adding or subtracting from xx?
  3. How would you determine the domain and range of this function?
  4. What happens if we reflect this function over the x-axis?
  5. Can you express this function in logarithmic form?

Tip:

In exponential decay functions like this, the rate of decay is determined by the base. The closer the base is to 0, the faster the function approaches the asymptote!

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Math Problem Analysis

Mathematical Concepts

Exponential Functions
Exponential Decay
Asymptotes
Intercepts
Logarithmic Functions

Formulas

g(x) = (1/4)^x - 2
y-intercept: g(0) = (1/4)^0 - 2
x-intercept: (1/4)^x - 2 = 0

Theorems

Properties of Exponential Decay
Logarithmic Properties

Suitable Grade Level

Grades 9-11