Math Problem Statement

differentiate x^(2(cos(x)))

Solution

To differentiate f(x)=x2cos(x)f(x) = x^{2\cos(x)}, we'll use logarithmic differentiation because the variable xx is both the base and appears in the exponent. Here's the step-by-step process:


Step 1: Take the natural logarithm

Take the natural logarithm of both sides: ln(f(x))=ln(x2cos(x))\ln(f(x)) = \ln\left(x^{2\cos(x)}\right)

Using the logarithmic property ln(ab)=bln(a)\ln(a^b) = b \ln(a), this becomes: ln(f(x))=2cos(x)ln(x)\ln(f(x)) = 2\cos(x) \ln(x)


Step 2: Differentiate implicitly

Differentiate both sides with respect to xx. Remember to apply the product rule to 2cos(x)ln(x)2\cos(x) \ln(x) on the right-hand side: f(x)f(x)=ddx(2cos(x)ln(x))\frac{f'(x)}{f(x)} = \frac{d}{dx} \left( 2\cos(x) \ln(x) \right)

The derivative of 2cos(x)ln(x)2\cos(x) \ln(x) is: ddx(2cos(x)ln(x))=2(sin(x))ln(x)+2cos(x)1x\frac{d}{dx} \left( 2\cos(x) \ln(x) \right) = 2(-\sin(x))\ln(x) + 2\cos(x)\frac{1}{x}

So: f(x)f(x)=2sin(x)ln(x)+2cos(x)x\frac{f'(x)}{f(x)} = -2\sin(x)\ln(x) + \frac{2\cos(x)}{x}


Step 3: Solve for f(x)f'(x)

Multiply through by f(x)=x2cos(x)f(x) = x^{2\cos(x)}: f(x)=x2cos(x)(2sin(x)ln(x)+2cos(x)x)f'(x) = x^{2\cos(x)} \left( -2\sin(x)\ln(x) + \frac{2\cos(x)}{x} \right)


Final Answer:

The derivative of f(x)=x2cos(x)f(x) = x^{2\cos(x)} is: f(x)=x2cos(x)(2sin(x)ln(x)+2cos(x)x)f'(x) = x^{2\cos(x)} \left( -2\sin(x)\ln(x) + \frac{2\cos(x)}{x} \right)

Would you like to see this expressed in more compact notation, or do you have further questions?


5 Related Questions:

  1. How do we apply logarithmic differentiation to other functions involving both variable bases and exponents?
  2. What are common scenarios where logarithmic differentiation is necessary?
  3. How can we use the product rule effectively in compound differentiation problems?
  4. Can you provide an example of integrating functions with variable bases and exponents?
  5. How does xa(x)x^{a(x)} compare to a(x)xa(x)^{x} in terms of differentiation?

Tip:

When faced with functions involving variables in both the base and exponent, logarithmic differentiation often simplifies the process significantly.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Logarithmic Differentiation
Trigonometry

Formulas

Derivative of ln(f(x)): d/dx[ln(f(x))] = f'(x)/f(x)
Logarithmic property: ln(a^b) = b * ln(a)
Product rule: d/dx[u*v] = u'*v + u*v'
Chain rule

Theorems

Logarithmic Differentiation Theorem
Properties of Exponential and Logarithmic Functions

Suitable Grade Level

Grades 11-12 or College Level