Math Problem Statement

Evaluate the limit: \lim_{x \to 2} \frac{\sqrt{x-2 + x^2 -3x + 2}}{\sqrt{x^2 - 4}}

Solution

The mathematical expression provided in the image is:

limx2x2+x23x+2x24\lim_{x \to 2} \frac{\sqrt{x-2 + x^2 -3x + 2}}{\sqrt{x^2 - 4}}

To evaluate this limit, we can simplify the expressions in the numerator and the denominator:

  1. Numerator: x2+x23x+2x - 2 + x^2 - 3x + 2 simplifies to x22x+2x^2 - 2x + 2.

  2. Denominator: x24x^2 - 4 can be factored using the difference of squares formula: (x2)(x+2)(x-2)(x+2).

Substituting back into the limit expression:

limx2x22x+2(x2)(x+2)\lim_{x \to 2} \frac{\sqrt{x^2 - 2x + 2}}{\sqrt{(x-2)(x+2)}}

Evaluating directly by substituting x=2x = 2:

  • In the numerator: 2222+2=2\sqrt{2^2 - 2 \cdot 2 + 2} = \sqrt{2}.
  • In the denominator: (22)(2+2)=04=0\sqrt{(2-2)(2+2)} = \sqrt{0 \cdot 4} = 0.

This forms a 00\frac{0}{0} indeterminate form, suggesting we need to apply L'Hôpital's rule or simplify further.

Applying L'Hôpital's Rule:

[ \lim_{x \to 2} \frac{\frac{d}{dx}[\sqrt{x^2 - 2x + 2}]}{\frac{d}{dx}[\sqrt{(x-2)(x+2)}]} ]

Let's compute the derivatives of the numerator and denominator:

  • Numerator Derivative: Use the chain rule: ddx[x22x+2]=12x22x+22(x1)=x1x22x+2\frac{d}{dx}[\sqrt{x^2 - 2x + 2}] = \frac{1}{2\sqrt{x^2 - 2x + 2}} \cdot 2(x - 1) = \frac{x-1}{\sqrt{x^2 - 2x + 2}}

  • Denominator Derivative: Again use the chain rule: ddx[(x2)(x+2)]=12(x2)(x+2)(2x)=x(x2)(x+2)\frac{d}{dx}[\sqrt{(x-2)(x+2)}] = \frac{1}{2\sqrt{(x-2)(x+2)}} \cdot (2x) = \frac{x}{\sqrt{(x-2)(x+2)}}

Substituting these back into the limit gives:

limx2x1x22x+2x(x2)(x+2)\lim_{x \to 2} \frac{\frac{x-1}{\sqrt{x^2 - 2x + 2}}}{\frac{x}{\sqrt{(x-2)(x+2)}}}

Simplifying further:

limx2x1x(x2)(x+2)x22x+2\lim_{x \to 2} \frac{x-1}{x} \cdot \frac{\sqrt{(x-2)(x+2)}}{\sqrt{x^2 - 2x + 2}}

We substitute x=2x = 2 directly:

21202=0\frac{2-1}{2} \cdot \frac{\sqrt{0}}{\sqrt{2}} = 0

Thus, the limit is 00.

Would you like to delve deeper into any part of this process, or do you have any other questions on different topics?

Further Exploration Questions:

  1. How does L'Hôpital's Rule apply when the limit still results in an indeterminate form after the first application?
  2. What are other techniques to handle limits involving square roots?
  3. How do we factor quadratic expressions like x22x+2x^2 - 2x + 2?
  4. Can we discuss the geometrical interpretation of the limit problem?
  5. What is the significance of indeterminate forms in calculus?

Tip: When dealing with complex limits, always consider simplifying expressions and checking for indeterminate forms before applying advanced techniques like L'Hôpital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Indeterminate Forms
Square Roots
L'Hôpital's Rule

Formulas

L'Hôpital's Rule: \lim_{x \to a} \frac{f(x)}{g(x)} = \lim_{x \to a} \frac{f'(x)}{g'(x)}
Quadratic simplification: x^2 - 2x + 2
Difference of squares: x^2 - 4 = (x - 2)(x + 2)

Theorems

L'Hôpital's Rule
Difference of Squares

Suitable Grade Level

Undergraduate Calculus