Math Problem Statement

Find \(\frac{f(x+h) - f(x)}{h}\) for the function \( f(x) = \frac{1}{\sqrt{3x - 2}} \) as \( h \to 0 \).

Solution

The image shows a mathematical problem asking to find the difference quotient f(x+h)f(x)h\frac{f(x+h) - f(x)}{h} for the given function f(x)=13x2f(x) = \frac{1}{\sqrt{3x - 2}} as h0h \to 0.

Solution:

The difference quotient is a fundamental part of finding the derivative. Let's proceed step-by-step.

  1. Function f(x)f(x): f(x)=13x2f(x) = \frac{1}{\sqrt{3x - 2}}

  2. Function f(x+h)f(x+h): Substitute x+hx + h into the function: f(x+h)=13(x+h)2=13x+3h2f(x + h) = \frac{1}{\sqrt{3(x + h) - 2}} = \frac{1}{\sqrt{3x + 3h - 2}}

  3. Difference Quotient: Now, apply the formula for the difference quotient: f(x+h)f(x)h=13x+3h213x2h\frac{f(x + h) - f(x)}{h} = \frac{\frac{1}{\sqrt{3x + 3h - 2}} - \frac{1}{\sqrt{3x - 2}}}{h} To simplify this, combine the terms in the numerator: f(x+h)f(x)h=3x23x+3h2h3x+3h23x2\frac{f(x + h) - f(x)}{h} = \frac{\sqrt{3x - 2} - \sqrt{3x + 3h - 2}}{h \cdot \sqrt{3x + 3h - 2} \cdot \sqrt{3x - 2}} The next step is to simplify the numerator using a technique called "rationalizing the numerator," multiplying both the numerator and the denominator by the conjugate of the numerator: Conjugate=3x2+3x+3h2\text{Conjugate} = \sqrt{3x - 2} + \sqrt{3x + 3h - 2} This gives: (3x23x+3h2)(3x2+3x+3h2)h(3x+3h23x2)(3x2+3x+3h2)\frac{\left( \sqrt{3x - 2} - \sqrt{3x + 3h - 2} \right) \left( \sqrt{3x - 2} + \sqrt{3x + 3h - 2} \right)}{h \cdot \left( \sqrt{3x + 3h - 2} \cdot \sqrt{3x - 2} \right) \left( \sqrt{3x - 2} + \sqrt{3x + 3h - 2} \right)} The numerator becomes: (3x2)(3x+3h2)=3h(3x - 2) - (3x + 3h - 2) = -3h Now the expression is: 3hh(3x+3h23x2)(3x2+3x+3h2)\frac{-3h}{h \cdot \left( \sqrt{3x + 3h - 2} \cdot \sqrt{3x - 2} \right) \left( \sqrt{3x - 2} + \sqrt{3x + 3h - 2} \right)} Simplifying: 33x+3h23x2(3x2+3x+3h2)\frac{-3}{\sqrt{3x + 3h - 2} \cdot \sqrt{3x - 2} \cdot \left( \sqrt{3x - 2} + \sqrt{3x + 3h - 2} \right)}

  4. Taking the Limit as h0h \to 0: As h0h \to 0, 3x+3h23x2\sqrt{3x + 3h - 2} \to \sqrt{3x - 2}. So the expression simplifies to: 32(3x2)3\frac{-3}{2 \cdot \left( \sqrt{3x - 2} \right)^3} Therefore, the derivative of the function f(x)f(x) is: f(x)=32(3x2)3/2f'(x) = \frac{-3}{2(3x - 2)^{3/2}}

Would you like more details or have any questions?

Here are some related questions you might find interesting:

  1. What is the geometric interpretation of a derivative?
  2. How does the difference quotient relate to the concept of a tangent line?
  3. Can you apply this same process to a polynomial function?
  4. What is the importance of rationalizing the numerator in calculus?
  5. How would the derivative change if the function were f(x)=1axbf(x) = \frac{1}{\sqrt{ax - b}}?

Tip: Rationalizing the numerator is an essential algebraic technique to simplify expressions, especially when finding limits and derivatives.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Limits

Formulas

Difference Quotient: \( \frac{f(x+h) - f(x)}{h} \)
Derivative of a function as the limit of the difference quotient

Theorems

Limit Definition of a Derivative

Suitable Grade Level

Grades 11-12 (Advanced High School Calculus)