Math Problem Statement

lim (x -> 2) (x^2 - 8)/(x - 2) + (x^2 - 2x)/(2x - 4)

Solution

The problem you have shared is asking for the limit of a sum of rational functions as xx approaches 2:

limx2(x28x2+x22x2x4)\lim_{{x \to 2}} \left( \frac{x^2 - 8}{x - 2} + \frac{x^2 - 2x}{2x - 4} \right)

Let's break it down and solve the limit:

Step 1: Factor the expressions

  1. For the first term, x28x2\frac{x^2 - 8}{x - 2}: We can't directly factor x28x^2 - 8 easily, so we'll leave it as is for now.

  2. For the second term, x22x2x4\frac{x^2 - 2x}{2x - 4}:

    • Factor 2x42x - 4 as 2(x2)2(x - 2).
    • The numerator x22xx^2 - 2x can be factored as x(x2)x(x - 2).

Thus, the second term becomes: x(x2)2(x2)\frac{x(x - 2)}{2(x - 2)} Canceling (x2)(x - 2), we get: x2\frac{x}{2}

So, the expression now becomes: limx2(x28x2+x2)\lim_{{x \to 2}} \left( \frac{x^2 - 8}{x - 2} + \frac{x}{2} \right)

Step 2: Simplify the first term using L'Hopital's Rule

For the first term x28x2\frac{x^2 - 8}{x - 2}, direct substitution of x=2x = 2 leads to an indeterminate form 00\frac{0}{0}. So, we apply L'Hopital's Rule by taking the derivative of the numerator and denominator: Derivative of x28=2x,Derivative of x2=1\text{Derivative of } x^2 - 8 = 2x, \quad \text{Derivative of } x - 2 = 1 So, the first term simplifies to: limx22x1=4\lim_{{x \to 2}} \frac{2x}{1} = 4

Step 3: Compute the overall limit

Now we compute the limit of the whole expression: limx2(4+x2)=4+22=4+1=5\lim_{{x \to 2}} \left( 4 + \frac{x}{2} \right) = 4 + \frac{2}{2} = 4 + 1 = 5

Final Answer:

limx2(x28x2+x22x2x4)=5\lim_{{x \to 2}} \left( \frac{x^2 - 8}{x - 2} + \frac{x^2 - 2x}{2x - 4} \right) = 5

Would you like more details or have any questions about this solution?


Here are 5 related questions to explore:

  1. What is L'Hopital's Rule, and when is it used in limits?
  2. How do you handle indeterminate forms in limits without using L'Hopital's Rule?
  3. Can all rational functions be simplified using factoring?
  4. How can limits help in finding the slope of a curve at a specific point?
  5. What are other techniques for solving limits aside from L'Hopital's Rule?

Tip: Always check if you can simplify an expression before applying complex techniques like L'Hopital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Factorization
L'Hopital's Rule

Formulas

L'Hopital's Rule: lim (x -> c) f(x)/g(x) = lim (x -> c) f'(x)/g'(x), if the limit results in 0/0 or ∞/∞
Factorization: x^2 - 2x = x(x - 2)

Theorems

L'Hopital's Rule
Limit Theorem

Suitable Grade Level

Grade 11-12 (High School Calculus)