Math Problem Statement

Evaluate the limit numerically or state that the limit does not exist.

Solution

The problem asks you to evaluate the limit of the given function as xx approaches 3:

limx3x25x+6x26x+9\lim_{x \to 3} \frac{x^2 - 5x + 6}{x^2 - 6x + 9}

Let's solve this step by step.

Step 1: Substitute x=3x = 3 into the expression

Substituting x=3x = 3 directly into the function:

325(3)+6326(3)+9=915+6918+9=00\frac{3^2 - 5(3) + 6}{3^2 - 6(3) + 9} = \frac{9 - 15 + 6}{9 - 18 + 9} = \frac{0}{0}

This gives us an indeterminate form 00\frac{0}{0}, which means we need to simplify the expression further to evaluate the limit.

Step 2: Factor the numerator and the denominator

Let's factor both the numerator and the denominator.

  1. Numerator: x25x+6x^2 - 5x + 6 x25x+6=(x2)(x3)x^2 - 5x + 6 = (x - 2)(x - 3)

  2. Denominator: x26x+9x^2 - 6x + 9 x26x+9=(x3)(x3)=(x3)2x^2 - 6x + 9 = (x - 3)(x - 3) = (x - 3)^2

Now, the function becomes:

(x2)(x3)(x3)2\frac{(x - 2)(x - 3)}{(x - 3)^2}

Step 3: Simplify the expression

We can cancel out the common factor (x3)(x - 3) from the numerator and the denominator:

(x2)(x3)(x3)2=x2x3 for x3\frac{(x - 2)(x - 3)}{(x - 3)^2} = \frac{x - 2}{x - 3} \text{ for } x \neq 3

However, because we are taking the limit as xx approaches 3, the expression simplifies to:

limx3x2x3\lim_{x \to 3} \frac{x - 2}{x - 3}

Step 4: Evaluate the limit

Substitute x=3x = 3 into the simplified expression:

limx3x2x3=3233=10\lim_{x \to 3} \frac{x - 2}{x - 3} = \frac{3 - 2}{3 - 3} = \frac{1}{0}

Step 5: Interpret the result

The result 10\frac{1}{0} suggests that the limit does not exist because dividing by zero leads to an undefined value. Since the numerator is positive and the denominator approaches zero, this indicates that the limit tends to infinity or negative infinity depending on the direction of approach.

Conclusion: The limit does not exist in a finite sense. It tends toward ++\infty or -\infty depending on the direction of approach.

Would you like further details or have any questions?

Here are some related questions to consider:

  1. How can you determine if a limit tends towards ++\infty or -\infty in such cases?
  2. What is the significance of the indeterminate form 00\frac{0}{0} in calculus?
  3. How can limits be evaluated using L'Hopital's Rule?
  4. Can all rational functions be simplified by factoring, as in this example?
  5. How does the concept of a removable discontinuity relate to this problem?

Tip: When faced with indeterminate forms like 00\frac{0}{0}, try simplifying the expression by factoring or using algebraic manipulation before considering advanced techniques like L'Hopital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Factoring
Indeterminate Forms

Formulas

Limit definition: \( \lim_{x \to c} f(x) \)
Factoring: \( x^2 - 5x + 6 = (x - 2)(x - 3) \)
Indeterminate form \( \frac{0}{0} \)

Theorems

Factoring method to simplify expressions
Limits involving indeterminate forms

Suitable Grade Level

Grades 11-12