Math Problem Statement

Consider the following function.

f(x) = ln(x) + 6

(a) What are the domain and range of f? (Enter your answers using interval notation.)

domain

range

(b) What is the x-intercept of the graph of f?

Solution

Let's analyze the function f(x)=ln(x)+6f(x) = \ln(x) + 6 in parts:

(a) Domain and Range of f(x)f(x)

Domain:

The function involves the natural logarithm, ln(x)\ln(x), which is only defined when x>0x > 0. Therefore, the domain is all positive real numbers. In interval notation, this is:

Domain:(0,)\text{Domain}: (0, \infty)

Range:

The logarithmic function ln(x)\ln(x) takes values from -\infty to \infty as xx increases from 0 to infinity. Since the function adds 6 to ln(x)\ln(x), the range is also shifted up by 6, meaning:

Range:(+6,+6)=(,)\text{Range}: (-\infty + 6, \infty + 6) = (-\infty, \infty)

Thus, the range is all real numbers:

Range:(,)\text{Range}: (-\infty, \infty)

(b) xx-intercept of the graph of ff

To find the xx-intercept, we set f(x)=0f(x) = 0 and solve for xx:

f(x)=ln(x)+6=0f(x) = \ln(x) + 6 = 0

ln(x)=6\ln(x) = -6

Now, solve for xx by exponentiating both sides:

x=e6x = e^{-6}

Thus, the xx-intercept is at x=e6x = e^{-6}.

Summary of answers:

(a)

  • Domain: (0,)(0, \infty)
  • Range: (,)(-\infty, \infty)

(b)

  • xx-intercept: x=e6x = e^{-6}

Would you like more details on any part of the solution?

Here are 5 related questions:

  1. What is the behavior of f(x)f(x) as x0+x \to 0^+?
  2. How would the graph of f(x)=ln(x)+6f(x) = \ln(x) + 6 compare to f(x)=ln(x)f(x) = \ln(x)?
  3. What happens to the range of f(x)f(x) if we change the constant from 6 to 2?
  4. What is the derivative of f(x)=ln(x)+6f(x) = \ln(x) + 6?
  5. How does the yy-intercept compare between logarithmic functions with different constants?

Tip: For functions involving logarithms, always check the domain carefully, as logarithms are only defined for positive values of xx.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Functions
Domain and Range
x-intercepts

Formulas

f(x) = ln(x) + 6
x = e^{-6}

Theorems

Properties of Logarithms
Definition of Natural Logarithm

Suitable Grade Level

Grades 10-12