Math Problem Statement

Match the functions with their graphs. Enter the letter of the graph below which corresponds to the function.

  1. 𝑓(π‘₯)=βˆ’lnπ‘₯
  2. 𝑓(π‘₯)=2+lnπ‘₯
  3. 𝑓(π‘₯)=ln(2βˆ’π‘₯)
  4. 𝑓(π‘₯)=ln(π‘₯βˆ’2)
  5. 𝑓(π‘₯)=βˆ’ln(βˆ’π‘₯)

Solution

To match the functions with their graphs, let's break down the key characteristics of each logarithmic function:

1. f(x)=βˆ’ln⁑(x)f(x) = -\ln(x)

  • This is a reflection of ln⁑(x)\ln(x) across the x-axis.
  • The graph approaches βˆ’βˆž-\infty as xβ†’0+x \to 0^+ and approaches 0 from below as xβ†’βˆžx \to \infty.
  • The domain is x>0x > 0.

2. f(x)=2+ln⁑(x)f(x) = 2 + \ln(x)

  • This is a vertical shift of ln⁑(x)\ln(x) upwards by 2 units.
  • The graph behaves like ln⁑(x)\ln(x), but every point is 2 units higher.
  • The domain is x>0x > 0, and it has a vertical asymptote at x=0x = 0.

3. f(x)=ln⁑(2βˆ’x)f(x) = \ln(2 - x)

  • This is a reflection of ln⁑(x)\ln(x), horizontally shifted right by 2 units.
  • The graph is defined for x<2x < 2, and has a vertical asymptote at x=2x = 2.
  • As xβ†’2βˆ’x \to 2^-, the graph approaches βˆ’βˆž-\infty, and as xβ†’βˆ’βˆžx \to -\infty, the graph rises slowly.

4. f(x)=ln⁑(xβˆ’2)f(x) = \ln(x - 2)

  • This is a horizontal shift of ln⁑(x)\ln(x) to the right by 2 units.
  • The graph is defined for x>2x > 2, with a vertical asymptote at x=2x = 2.
  • As xβ†’2+x \to 2^+, the graph approaches βˆ’βˆž-\infty, and as xβ†’βˆžx \to \infty, the graph rises slowly.

5. f(x)=βˆ’ln⁑(βˆ’x)f(x) = -\ln(-x)

  • This is a reflection of ln⁑(βˆ’x)\ln(-x) across the x-axis.
  • The graph is defined for x<0x < 0, with a vertical asymptote at x=0x = 0.
  • As xβ†’0βˆ’x \to 0^-, the graph approaches +∞+\infty, and as xβ†’βˆ’βˆžx \to -\infty, the graph approaches 0 from above.

Now, you can match these descriptions with the corresponding graphs by analyzing the domain, asymptotes, and general behavior of each function.

Do you have the graphs available for me to match them precisely, or should I help further with how to approach graph identification?


Follow-up questions:

  1. What is the domain of ln⁑(x)\ln(x), and how does it impact transformations?
  2. How does reflecting a logarithmic function across the x-axis affect its shape?
  3. How do vertical and horizontal shifts affect the graph of logarithmic functions?
  4. What is the significance of vertical asymptotes in the behavior of logarithmic functions?
  5. How can you determine if a function's graph is defined for positive or negative values of xx?

Tip:

Logarithmic functions are undefined for non-positive values of their arguments, so always check the domain carefully when shifting or reflecting graphs.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Functions
Transformations of Functions
Asymptotes
Reflections

Formulas

f(x) = ln(x) (Natural Logarithm)
f(x) = -ln(x) (Reflection across the x-axis)
f(x) = ln(x - a) (Horizontal shift)
f(x) = ln(a - x) (Reflection and shift)

Theorems

Properties of Logarithmic Functions
Domain and Range of Logarithms
Vertical Asymptotes in Logarithmic Functions

Suitable Grade Level

Grades 10-12