Math Problem Statement

lim x->2 (x^2 / (x^4 - 16))

Solution

The limit problem in the image is:

limx2x2x416\lim_{{x \to 2}} \frac{x^2}{x^4 - 16}

Let's solve this step-by-step:

Step 1: Direct Substitution

First, substitute x=2x = 2 into the expression:

222416=41616=40\frac{2^2}{2^4 - 16} = \frac{4}{16 - 16} = \frac{4}{0}

This results in a division by zero, which means the direct substitution does not work. We need to simplify the expression further.

Step 2: Factor the Denominator

The denominator is x416x^4 - 16, which is a difference of squares:

x416=(x24)(x2+4)x^4 - 16 = (x^2 - 4)(x^2 + 4)

We can further factor x24x^2 - 4 as:

x24=(x2)(x+2)x^2 - 4 = (x - 2)(x + 2)

So the denominator becomes:

x416=(x2)(x+2)(x2+4)x^4 - 16 = (x - 2)(x + 2)(x^2 + 4)

Step 3: Simplify the Expression

The limit expression now becomes:

limx2x2(x2)(x+2)(x2+4)\lim_{{x \to 2}} \frac{x^2}{(x - 2)(x + 2)(x^2 + 4)}

Since x2x - 2 is a factor in the denominator, we cannot directly substitute x=2x = 2. But we can attempt to simplify it further.

Step 4: Use L'Hopital's Rule

Since direct substitution leads to an indeterminate form of 00\frac{0}{0}, we can apply L'Hopital's Rule, which states that if limxaf(x)g(x)\lim_{{x \to a}} \frac{f(x)}{g(x)} results in 00\frac{0}{0}, we can differentiate the numerator and denominator and then take the limit.

  • Differentiate the numerator: ddx(x2)=2x\frac{d}{dx}(x^2) = 2x
  • Differentiate the denominator: ddx((x2)(x+2)(x2+4))\frac{d}{dx}((x - 2)(x + 2)(x^2 + 4))

I'll calculate that.After applying L'Hopital's Rule and differentiating both the numerator and the denominator, the limit as x2x \to 2 is:

limx2x2x416=18\lim_{{x \to 2}} \frac{x^2}{x^4 - 16} = \frac{1}{8}

Would you like more details on the differentiation steps, or do you have any other questions?

Here are some related questions you might find helpful:

  1. How does L'Hopital's Rule work, and when can you apply it?
  2. What are indeterminate forms, and why do they arise in limits?
  3. Can we solve this limit without using L'Hopital's Rule?
  4. How do you factor higher-order polynomials like x416x^4 - 16?
  5. What is the significance of the result 18\frac{1}{8} in this context?

Tip: Always check if a limit results in an indeterminate form (00\frac{0}{0} or \frac{\infty}{\infty}) before applying L'Hopital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Factorization
Indeterminate Forms
L'Hopital's Rule

Formulas

x^4 - 16 = (x^2 - 4)(x^2 + 4)
x^2 - 4 = (x - 2)(x + 2)
L'Hopital's Rule: lim x->a [f'(x) / g'(x)] if lim x->a [f(x) / g(x)] = 0/0

Theorems

L'Hopital's Rule
Difference of Squares

Suitable Grade Level

Grades 11-12