Math Problem Statement

Find f(x) given that: f'(x) = 1/x and f(e) =2

Solution

To find f(x)f(x), we need to integrate the given derivative f(x)=1xf'(x) = \frac{1}{x} and then apply the condition f(e)=2f(e) = 2 to determine the constant of integration.

Step 1: Integrate f(x)f'(x)

f(x)=1xdxf(x) = \int \frac{1}{x} \, dx The integral of 1x\frac{1}{x} is the natural logarithm: f(x)=lnx+Cf(x) = \ln|x| + C where CC is the constant of integration.

Step 2: Apply the condition f(e)=2f(e) = 2

Substitute x=ex = e into the equation: f(e)=lne+C=2f(e) = \ln|e| + C = 2 Since ln(e)=1\ln(e) = 1, the equation becomes: 1+C=21 + C = 2 Solving for CC, we get: C=1C = 1

Step 3: Final function

Thus, the function f(x)f(x) is: f(x)=lnx+1f(x) = \ln|x| + 1

Would you like more details or have any questions?

Here are five related questions:

  1. What are the properties of the natural logarithm function ln(x)\ln(x)?
  2. How does the constant of integration affect the solution?
  3. What would happen if the condition f(e)=2f(e) = 2 were different?
  4. Can we determine the behavior of f(x)f(x) as xx approaches 0 or infinity?
  5. How would the solution change if f(x)f'(x) were 2x\frac{2}{x} instead of 1x\frac{1}{x}?

Tip: Always check initial or boundary conditions after integrating to find the unknown constant!

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Math Problem Analysis

Mathematical Concepts

Calculus
Integration
Logarithmic Functions

Formulas

f'(x) = 1/x
f(x) = ∫(1/x) dx
f(x) = ln|x| + C

Theorems

Fundamental Theorem of Calculus
Natural Logarithm Properties

Suitable Grade Level

Grades 11-12