Math Problem Statement

If f(x) = x x+2 , (a) Find f ′ (x)

Solution

Given the function f(x)=xx+2f(x) = \frac{x}{x+2}, we want to find its derivative f(x)f'(x).

Step 1: Apply the Quotient Rule

The quotient rule is used when we have a function in the form g(x)h(x)\frac{g(x)}{h(x)}. The derivative is given by:

ddx(g(x)h(x))=g(x)h(x)g(x)h(x)[h(x)]2\frac{d}{dx} \left( \frac{g(x)}{h(x)} \right) = \frac{g'(x)h(x) - g(x)h'(x)}{[h(x)]^2}

For f(x)=xx+2f(x) = \frac{x}{x+2}, we can set:

  • g(x)=xg(x) = x
  • h(x)=x+2h(x) = x+2

Step 2: Differentiate g(x)g(x) and h(x)h(x)

  • g(x)=ddx(x)=1g'(x) = \frac{d}{dx} (x) = 1
  • h(x)=ddx(x+2)=1h'(x) = \frac{d}{dx} (x+2) = 1

Step 3: Apply the Quotient Rule

Now, applying the quotient rule:

f(x)=1(x+2)x1(x+2)2f'(x) = \frac{1 \cdot (x+2) - x \cdot 1}{(x+2)^2}

Simplifying the numerator:

f(x)=x+2x(x+2)2=2(x+2)2f'(x) = \frac{x+2 - x}{(x+2)^2} = \frac{2}{(x+2)^2}

Thus, the derivative of f(x)f(x) is:

f(x)=2(x+2)2f'(x) = \frac{2}{(x+2)^2}

Do you want more details or have any questions?

Here are 5 related questions for further practice:

  1. What is the second derivative of f(x)=xx+2f(x) = \frac{x}{x+2}?
  2. Find the derivative of f(x)=x2x+3f(x) = \frac{x^2}{x+3} using the quotient rule.
  3. What is the derivative of f(x)=1x+2f(x) = \frac{1}{x+2}?
  4. How do you apply the product rule and quotient rule together?
  5. Can you differentiate f(x)=xx2+1f(x) = \frac{x}{x^2+1}?

Tip: Always remember to simplify the numerator after applying the quotient rule to avoid calculation errors!

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Quotient Rule

Formulas

Quotient Rule: d/dx [g(x)/h(x)] = (g'(x)h(x) - g(x)h'(x)) / [h(x)]^2

Theorems

Quotient Rule

Suitable Grade Level

Grades 11-12, Calculus 1