Math Problem Statement

Use logarithmic differentiation to find the derivative of the function: y = (sin^2(x) * tan^6(x)) / (x^2 + 3)^2.

Solution

To solve for yy' using logarithmic differentiation, let's go through the following steps:

Given: y=sin2(x)tan6(x)(x2+3)2y = \frac{\sin^2(x) \cdot \tan^6(x)}{(x^2 + 3)^2}

Step 1: Take the Natural Logarithm of Both Sides

Applying the natural logarithm to both sides, we get: ln(y)=ln(sin2(x)tan6(x)(x2+3)2)\ln(y) = \ln\left(\frac{\sin^2(x) \cdot \tan^6(x)}{(x^2 + 3)^2}\right)

Using logarithmic properties (specifically, lnab=lnalnb\ln \frac{a}{b} = \ln a - \ln b and ln(ab)=lna+lnb\ln(ab) = \ln a + \ln b), this becomes: ln(y)=ln(sin2(x))+ln(tan6(x))ln((x2+3)2)\ln(y) = \ln(\sin^2(x)) + \ln(\tan^6(x)) - \ln((x^2 + 3)^2)

Now we can simplify further by bringing down the exponents: ln(y)=2ln(sin(x))+6ln(tan(x))2ln(x2+3)\ln(y) = 2 \ln(\sin(x)) + 6 \ln(\tan(x)) - 2 \ln(x^2 + 3)

Step 2: Differentiate Both Sides with Respect to xx

Now, differentiate implicitly with respect to xx:

1yy=2cos(x)sin(x)+61tan(x)sec2(x)22xx2+3\frac{1}{y} \cdot y' = 2 \cdot \frac{\cos(x)}{\sin(x)} + 6 \cdot \frac{1}{\tan(x)} \cdot \sec^2(x) - 2 \cdot \frac{2x}{x^2 + 3}

This simplifies to: yy=2cot(x)+6sec2(x)4xx2+3\frac{y'}{y} = 2 \cot(x) + 6 \sec^2(x) - \frac{4x}{x^2 + 3}

Step 3: Solve for yy'

Now, multiply both sides by yy to isolate yy': y=y(2cot(x)+6sec2(x)4xx2+3)y' = y \cdot \left(2 \cot(x) + 6 \sec^2(x) - \frac{4x}{x^2 + 3}\right)

Finally, substitute back the expression for yy: y=sin2(x)tan6(x)(x2+3)2(2cot(x)+6sec2(x)4xx2+3)y' = \frac{\sin^2(x) \cdot \tan^6(x)}{(x^2 + 3)^2} \cdot \left(2 \cot(x) + 6 \sec^2(x) - \frac{4x}{x^2 + 3}\right)

This is the derivative yy' of the function.

Would you like more details on any part of this process or have any questions?

Here are five related questions for further practice:

  1. How would the process change if the exponent of sin(x)\sin(x) was 3 instead of 2?
  2. Can you use logarithmic differentiation on a product involving exponential and trigonometric functions?
  3. How do you simplify expressions involving cot(x)\cot(x) and sec2(x)\sec^2(x) after differentiation?
  4. What if we applied logarithmic differentiation to only the numerator? Would that be valid?
  5. How does the derivative of a function change if it’s under a square root?

Tip: When using logarithmic differentiation, always simplify by expanding the log expression first before differentiating—it makes the process more straightforward.

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Math Problem Analysis

Mathematical Concepts

Logarithmic Differentiation
Implicit Differentiation
Trigonometric Functions
Derivative Rules

Formulas

ln(a * b) = ln(a) + ln(b)
ln(a / b) = ln(a) - ln(b)
Derivative of ln(f(x)) with respect to x is f'(x) / f(x)

Theorems

Product Rule
Quotient Rule
Chain Rule

Suitable Grade Level

Grades 11-12 or Calculus level