Math Problem Statement

derive square root x^2+2x+3/ln(x)

Solution

We are tasked with finding the derivative of the function:

f(x)=x2+2x+3ln(x)f(x) = \sqrt{\frac{x^2 + 2x + 3}{\ln(x)}}

Step 1: Rewriting the function

We rewrite the square root as a fractional exponent: f(x)=(x2+2x+3ln(x))12f(x) = \left(\frac{x^2 + 2x + 3}{\ln(x)}\right)^{\frac{1}{2}}

Step 2: Apply the chain rule

Using the chain rule, the derivative of f(x)f(x) is: f(x)=12(x2+2x+3ln(x))12ddx(x2+2x+3ln(x))f'(x) = \frac{1}{2} \left(\frac{x^2 + 2x + 3}{\ln(x)}\right)^{-\frac{1}{2}} \cdot \frac{d}{dx} \left( \frac{x^2 + 2x + 3}{\ln(x)} \right)

This simplifies to: f(x)=12x2+2x+3ln(x)ddx(x2+2x+3ln(x))f'(x) = \frac{1}{2\sqrt{\frac{x^2 + 2x + 3}{\ln(x)}}} \cdot \frac{d}{dx} \left( \frac{x^2 + 2x + 3}{\ln(x)} \right)

Step 3: Differentiate the inner fraction

Let u(x)=x2+2x+3u(x) = x^2 + 2x + 3 and v(x)=ln(x)v(x) = \ln(x). Then the fraction can be written as u(x)v(x)\frac{u(x)}{v(x)}. Using the quotient rule: ddx(u(x)v(x))=u(x)v(x)u(x)v(x)(v(x))2\frac{d}{dx} \left( \frac{u(x)}{v(x)} \right) = \frac{u'(x)v(x) - u(x)v'(x)}{(v(x))^2}

Compute u(x)u'(x) and v(x)v'(x):

u(x)=2x+2,v(x)=ln(x),v(x)=1xu'(x) = 2x + 2, \quad v(x) = \ln(x), \quad v'(x) = \frac{1}{x}

Substitute into the quotient rule:

ddx(u(x)v(x))=(2x+2)ln(x)(x2+2x+3)1x(ln(x))2\frac{d}{dx} \left( \frac{u(x)}{v(x)} \right) = \frac{(2x + 2)\ln(x) - (x^2 + 2x + 3)\frac{1}{x}}{(\ln(x))^2}

Simplify the terms:

= \frac{(2x + 2)\ln(x) - (x + 2 + \frac{3}{x})}{(\ln(x))^2}$$ ### Step 4: Final expression for $$f'(x)$$ Substitute this result back into the derivative of $$f(x)$$: $$f'(x) = \frac{1}{2\sqrt{\frac{x^2 + 2x + 3}{\ln(x)}}} \cdot \frac{(2x + 2)\ln(x) - (x + 2 + \frac{3}{x})}{(\ln(x))^2}$$ This is the derivative of the given function. It can be simplified further if needed. Would you like me to work through the simplification or provide an alternate explanation? --- ### Relative Questions: 1. What is the chain rule and how is it applied in derivatives? 2. How does the quotient rule help in differentiating fractions? 3. What happens if $$\ln(x)$$ is very small or approaches zero? 4. How can we simplify the derivative expression further? 5. How does the square root affect the differentiation process? ### Tip: When differentiating composite functions, always identify the outermost function first and apply the chain rule systematically.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Chain Rule
Quotient Rule
Logarithmic Functions
Square Root Functions

Formulas

Chain Rule: (f(g(x)))' = f'(g(x)) * g'(x)
Quotient Rule: (u/v)' = (u'v - uv') / v^2
Derivative of ln(x): d/dx[ln(x)] = 1/x

Theorems

Chain Rule
Quotient Rule

Suitable Grade Level

Undergraduate Calculus or Advanced High School Calculus