Math Problem Statement

graph a Logarithmic function

Solution

To graph a logarithmic function, let's start by considering a general logarithmic function of the form:

y=logb(x)y = \log_b(x)

Here:

  • bb is the base of the logarithm.
  • xx is the input variable.

Steps to Graph a Logarithmic Function:

  1. Identify the Base: Determine the base bb. If b>1b > 1, the function is increasing; if 0<b<10 < b < 1, the function is decreasing.

  2. Determine the Domain: The function is only defined for x>0x > 0, meaning that the graph exists only in the first quadrant.

  3. Find Key Points:

    • When x=1x = 1, y=logb(1)=0y = \log_b(1) = 0 (since any logarithm of 1 is 0).
    • When x=bx = b, y=logb(b)=1y = \log_b(b) = 1.
    • When x=1bx = \frac{1}{b}, y=logb(1b)=1y = \log_b\left(\frac{1}{b}\right) = -1.
  4. Asymptote: The graph has a vertical asymptote at x=0x = 0 because as xx approaches 0 from the right, the logarithmic function approaches negative infinity.

  5. Sketch the Graph:

    • Plot the key points found in step 3.
    • Draw the vertical asymptote at x=0x = 0.
    • Sketch the curve passing through the key points, making sure it approaches the asymptote but never crosses it.

Example: Graph y=log2(x)y = \log_2(x)

  1. Base: b=2b = 2 (so the function is increasing).

  2. Key Points:

    • (1,0)(1, 0)
    • (2,1)(2, 1)
    • (12,1)\left(\frac{1}{2}, -1\right)
  3. Vertical Asymptote: At x=0x = 0.

  4. Sketch: Plot the points and draw the curve approaching the asymptote at x=0x = 0.

Would you like me to plot this graph for you, or do you have any questions?


Related Questions:

  1. How does changing the base bb affect the graph of the logarithmic function?
  2. What is the relationship between logarithmic and exponential functions?
  3. How do you find the inverse of a logarithmic function?
  4. Can logarithmic functions have negative outputs?
  5. How do you solve equations involving logarithms?

Tip: Remember that the logarithm function is the inverse of the exponential function. Understanding this relationship can help in solving and graphing these functions effectively.

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Math Problem Analysis

Mathematical Concepts

Logarithms
Graphing Functions

Formulas

y = log_b(x)

Theorems

Properties of Logarithms
Inverse Function Theorem

Suitable Grade Level

Grades 10-12