Math Problem Statement

Find the derivative of y = (log_3 x)^2.

Solution

The problem is asking for the derivative of the function:

y=(log3x)2y = \left(\log_3 x\right)^2

To differentiate this function, let's apply the chain rule and the properties of logarithmic differentiation.

Step-by-Step Solution

  1. Rewrite the Function in Terms of a Natural Logarithm: Since log3x=lnxln3\log_3 x = \frac{\ln x}{\ln 3}, we can rewrite yy as: y=(lnxln3)2y = \left(\frac{\ln x}{\ln 3}\right)^2

  2. Differentiate Using the Chain Rule: Let u=lnxln3u = \frac{\ln x}{\ln 3}, so y=u2y = u^2. The derivative of yy with respect to xx is: dydx=2ududx\frac{dy}{dx} = 2u \cdot \frac{du}{dx}

  3. Differentiate uu with Respect to xx: Since u=lnxln3u = \frac{\ln x}{\ln 3}, we have: dudx=1xln3\frac{du}{dx} = \frac{1}{x \ln 3}

  4. Combine the Results: Substitute u=lnxln3u = \frac{\ln x}{\ln 3} and dudx=1xln3\frac{du}{dx} = \frac{1}{x \ln 3} back into the expression: dydx=2lnxln31xln3\frac{dy}{dx} = 2 \cdot \frac{\ln x}{\ln 3} \cdot \frac{1}{x \ln 3}

  5. Simplify: dydx=2lnxx(ln3)2\frac{dy}{dx} = \frac{2 \ln x}{x (\ln 3)^2}

Final Answer

dydx=2lnxx(ln3)2\frac{dy}{dx} = \frac{2 \ln x}{x (\ln 3)^2}

Would you like further clarification on any of these steps?

Here are some follow-up questions for deeper understanding:

  1. How does the chain rule apply in this problem?
  2. Can we generalize this approach for other bases of logarithms?
  3. What would happen if the power was different, say 33 instead of 22?
  4. How does this differentiation change if the argument of the logarithm, xx, was a more complex function?
  5. Why is it useful to rewrite logarithms in terms of natural logs?

Tip: Remember that converting logarithms to natural logarithms can simplify differentiation with unusual bases.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Logarithmic Differentiation

Formulas

Chain rule
Derivative of logarithmic functions
Conversion of logarithmic base

Theorems

Chain rule for differentiation

Suitable Grade Level

Grades 11-12