Math Problem Statement

which of the following statements about the natural logarithmic function y=In(x) is FALSA? A) the range of Y=In(X) goes from - infinity to 100. b) the function In(x) is increasing wherever it is defined. c) the function In(x) is concave down wherever it is defined. d) the domain for In(x) is x>0. e) In(e^4)=4

Solution

To determine which statement about the natural logarithmic function y=ln(x)y = \ln(x) is false, let's analyze each option one by one:

Analyzing Each Statement:

A) The range of y=ln(x)y = \ln(x) goes from -\infty to 100.

  • The range of y=ln(x)y = \ln(x) is actually from -\infty to ++\infty. There is no upper bound of 100; this statement is incorrect.

B) The function ln(x)\ln(x) is increasing wherever it is defined.

  • The natural logarithm function ln(x)\ln(x) is an increasing function for all x>0x > 0. This statement is correct.

C) The function ln(x)\ln(x) is concave down wherever it is defined.

  • The function ln(x)\ln(x) is concave down because its second derivative is negative (d2dx2ln(x)<0\frac{d^2}{dx^2} \ln(x) < 0). This statement is correct.

D) The domain for ln(x)\ln(x) is x>0x > 0.

  • The natural logarithm is defined only for positive values of xx, so the domain is x>0x > 0. This statement is correct.

E) ln(e4)=4\ln(e^4) = 4

  • This is true because ln(e4)=4\ln(e^4) = 4 follows directly from the logarithmic property ln(ea)=a\ln(e^a) = a. This statement is correct.

Conclusion:

The false statement is:

A) The range of y=ln(x)y = \ln(x) goes from -\infty to 100.

Would you like more details on any of these points or have any questions?

Here are some related questions to explore further:

  1. What is the derivative of the natural logarithmic function y=ln(x)y = \ln(x)?
  2. How do you determine the concavity of a function using the second derivative?
  3. Can the range of a function ever be limited, and if so, under what conditions?
  4. What are some other key properties of logarithmic functions?
  5. How do transformations affect the domain and range of logarithmic functions?

Tip: Remember that understanding the basic properties of logarithmic functions, such as their domain, range, and concavity, helps in identifying any erroneous statements quickly.

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Math Problem Analysis

Mathematical Concepts

Natural Logarithms
Functions
Concavity
Derivatives

Formulas

ln(x)
ln(e^a) = a
Second derivative test for concavity

Theorems

Properties of Logarithmic Functions
Domain and Range Theorem
Concavity Theorem

Suitable Grade Level

Grades 10-12