Math Problem Statement

Use your graphing calculator to produce a graph of the function. Then determine the domain and range of the function by looking at its graph. f left parenthesis x right parenthesis equals ln left parenthesis x plus 1 right parenthesis Question content area bottom Part 1 Identify the graph of the function f left parenthesis x right parenthesis equals ln left parenthesis x plus 1 right parenthesis. Choose the correct graph below. A.

A coordinate system has a horizontal axis labeled from negative 6 to 6 in increments of 1 and a vertical axis labeled from negative 6 to 6 in increments of 1. A curve rises steeply to the left of the vertical axis and then rises at a decreasing rate, passing through the points (5, 1.8) and (6, 1.9). As the curve approaches a horizontal cooridnate of negative 1 from the right, the curve approaches negative infinity. All coordinates are approximate. ​[negative 6​,6​] by ​[minus​6,6] B.

A coordinate system has a horizontal axis labeled from negative 2 to 10 in increments of 1 and a vertical axis labeled from negative 6 to 6 in increments of 1. A curve rises steeply to the right of the vertical axis and then rises at a decreasing rate, passing through (9, 2.1) and (10, 2.2). As the curve approaches a horizontal coordinate of 1 from the right, the curve approaches negative infinity. All coordinates are approximate. ​[negative 2​,10​] by ​[minus​6,6] C.

A coordinate system has a horizontal axis labeled from negative 6 to 6 in increments of 1 and a vertical axis labeled from negative 6 to 6 in increments of 1. A curve falls steeply to the left of the vertical axis and then falls at a decreasing rate, passing through the points (5, negative 1.8) and (6, negative 1.9). As the curve approaches a horizontal coordinate of negative 1 from the right, the curve approaches positive infinity. All coordinates are approximate. ​[negative 6​,6​] by ​[minus​6,6] D.

A coordinate system has a horizontal axis labeled from negative 2 to 10 in increments of 1 and a vertical axis labeled from negative 6 to 6 in increments of 1. A curve falls steeply to the right of the vertical axis and then falls at a decreasing rate, passing through (9, negative 2.1) and (10, negative 2.2). As the curve approaches a horizontal coordinate of 1 from the right, the curve approaches positive infinity. All coordinates are approximate. ​[negative 2​,10​] by ​[minus​6,6] Part 2 The domain of the function is    enter your response here. ​(Type your answer in interval​ notation.) Part 3 The range of the function is    enter your response here. ​(Type your answer in interval​ notation.)

Solution

Part 1: Identify the graph of the function f(x)=ln(x+1)f(x) = \ln(x + 1)

The function f(x)=ln(x+1)f(x) = \ln(x + 1) is a natural logarithmic function shifted left by 1 unit. It has the following key features:

  • The logarithmic function ln(x)\ln(x) has a vertical asymptote at x=0x = 0. For f(x)=ln(x+1)f(x) = \ln(x + 1), the vertical asymptote shifts left by 1 unit to x=1x = -1.
  • The function is undefined for x1x \leq -1 because the natural logarithm function is only defined for positive arguments.
  • The graph approaches negative infinity as xx approaches 1-1 from the right.
  • As xx \to \infty, f(x)f(x) \to \infty, but the rate of increase slows down.

The correct graph will show a vertical asymptote at x=1x = -1, with the curve increasing to the right of this asymptote. Based on this analysis:

  • Graph A best fits the description of f(x)=ln(x+1)f(x) = \ln(x + 1). The curve passes through points like (5, 1.8) and (6, 1.9) and rises at a decreasing rate while having a vertical asymptote at x=1x = -1.

Thus, the correct graph is Graph A.

Part 2: Domain of the function f(x)=ln(x+1)f(x) = \ln(x + 1)

For the function f(x)=ln(x+1)f(x) = \ln(x + 1), the argument x+1x + 1 must be greater than 0 for the logarithm to be defined: x+1>0    x>1x + 1 > 0 \implies x > -1 Thus, the domain of the function is (1,)(-1, \infty).

Domain: (1,)(-1, \infty)

Part 3: Range of the function f(x)=ln(x+1)f(x) = \ln(x + 1)

The natural logarithmic function ln(x+1)\ln(x + 1) can take any real value as x1x \to -1 from the right and approaches negative infinity, and as xx \to \infty, the function increases without bound. Therefore, the range of the function is all real numbers, (,)(-\infty, \infty).

Range: (,)(-\infty, \infty)


Do you have any questions or would you like more details?

Here are 5 related questions to deepen understanding:

  1. What is the effect of adding or subtracting a constant inside the logarithm function on its graph?
  2. How would the graph of f(x)=ln(x+2)f(x) = \ln(x + 2) differ from f(x)=ln(x+1)f(x) = \ln(x + 1)?
  3. How do you find the vertical asymptote of a logarithmic function?
  4. What happens to the domain and range if we reflect the function ln(x+1)\ln(x + 1) across the x-axis?
  5. What is the inverse function of f(x)=ln(x+1)f(x) = \ln(x + 1)?

Tip: Always remember that the natural logarithm function ln(x)\ln(x) is undefined for non-positive values of xx, which directly affects the domain of the function.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Functions
Domain and Range
Graphing

Formulas

f(x) = ln(x + 1)

Theorems

Properties of Logarithmic Functions
Domain and Range of Logarithmic Functions

Suitable Grade Level

Grades 10-12