Math Problem Statement

y=ln(lnx)

Solution

To analyze the function y=ln(ln(x))y = \ln(\ln(x)), let's go through a few key aspects:

1. Domain:

The function ln(x)\ln(x) is only defined for x>0x > 0. Additionally, for y=ln(ln(x))y = \ln(\ln(x)) to be defined, the inner function ln(x)\ln(x) must also be greater than 0:

ln(x)>0    x>1\ln(x) > 0 \implies x > 1

Thus, the domain of y=ln(ln(x))y = \ln(\ln(x)) is x>1x > 1.

2. Range:

Since the natural logarithm function ln(x)\ln(x) can take on any positive value for x>1x > 1, the function ln(ln(x))\ln(\ln(x)) can take any real value. Hence, the range of y=ln(ln(x))y = \ln(\ln(x)) is:

(,+)(-\infty, +\infty)

3. Derivative:

To find the derivative of y=ln(ln(x))y = \ln(\ln(x)), we use the chain rule:

[ \frac{dy}{dx} = \frac{d}{dx} [\ln(\ln(x))] = \frac{1}{\ln(x)} \cdot \frac{d}{dx} [\ln(x)] = \frac{1}{\ln(x)} \cdot \frac{1}{x} = \frac{1}{x \ln(x)} ]

So, the derivative of the function is:

dydx=1xln(x)\frac{dy}{dx} = \frac{1}{x \ln(x)}

4. Critical Points:

To find critical points, we set the derivative to zero:

1xln(x)=0\frac{1}{x \ln(x)} = 0

Since the expression 1xln(x)\frac{1}{x \ln(x)} is never zero for x>1x > 1, there are no critical points where the derivative is zero. However, we need to check the behavior at the boundary of the domain, x1+x \to 1^+.

5. Behavior at the Boundary:

As x1+x \to 1^+, we have:

ln(x)0+    ln(ln(x))\ln(x) \to 0^+ \implies \ln(\ln(x)) \to -\infty

Thus, the function decreases to negative infinity as xx approaches 1 from the right.

Conclusion:

  • Domain: x>1x > 1
  • Range: (,+)(-\infty, +\infty)
  • Derivative: dydx=1xln(x)\frac{dy}{dx} = \frac{1}{x \ln(x)}

Would you like more details or have any questions? Here are some related questions you might be interested in:

  1. What is the second derivative of y=ln(ln(x))y = \ln(\ln(x))?
  2. How do you find the concavity and inflection points of y=ln(ln(x))y = \ln(\ln(x))?
  3. How would you plot the function y=ln(ln(x))y = \ln(\ln(x))?
  4. How does the function behave as xx \to \infty?
  5. How can you apply logarithmic differentiation to more complex functions?

Tip: Remember that logarithmic functions have unique properties when it comes to growth rates and asymptotic behavior!

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Math Problem Analysis

Mathematical Concepts

Calculus
Logarithmic Functions
Differentiation

Formulas

y = ln(ln(x))
Derivative: dy/dx = 1 / (x ln(x))

Theorems

Chain Rule

Suitable Grade Level

Grades 11-12