Math Problem Statement

Find the limit: lim_{x→-3} |2x+6|/(x+3)

Solution

The limit given in the image is:

limx32x+6x+3\lim_{{x \to -3}} \frac{|2x + 6|}{x + 3}

Step-by-Step Solution:

  1. Analyze the Absolute Value: The expression inside the absolute value is 2x+62x + 6, which can be factored as: 2x+6=2(x+3)2x + 6 = 2(x + 3) Therefore: 2x+6=2(x+3)=2x+3|2x + 6| = |2(x + 3)| = 2|x + 3|

  2. Simplify the Limit: Substitute this into the original limit: limx32x+3x+3\lim_{{x \to -3}} \frac{2|x + 3|}{x + 3}

  3. Behavior Near x=3x = -3: The behavior of x+3|x + 3| depends on whether xx approaches 3-3 from the left or the right:

    • If x3x \to -3^- (approaching from the left), x+3<0x + 3 < 0, so x+3=(x+3)|x + 3| = -(x + 3).
    • If x3+x \to -3^+ (approaching from the right), x+3>0x + 3 > 0, so x+3=x+3|x + 3| = x + 3.
  4. Left-Hand Limit (x3x \to -3^-): In this case, x+3=(x+3)|x + 3| = -(x + 3), so: limx32x+3x+3=limx32((x+3))x+3=limx32(x+3)x+3\lim_{{x \to -3^-}} \frac{2|x + 3|}{x + 3} = \lim_{{x \to -3^-}} \frac{2(-(x + 3))}{x + 3} = \lim_{{x \to -3^-}} \frac{-2(x + 3)}{x + 3} For x3x \neq -3, this simplifies to 2-2. Thus, the left-hand limit is: limx32x+3x+3=2\lim_{{x \to -3^-}} \frac{2|x + 3|}{x + 3} = -2

  5. Right-Hand Limit (x3+x \to -3^+): In this case, x+3=x+3|x + 3| = x + 3, so: limx3+2x+3x+3=limx3+2(x+3)x+3=limx3+2=2\lim_{{x \to -3^+}} \frac{2|x + 3|}{x + 3} = \lim_{{x \to -3^+}} \frac{2(x + 3)}{x + 3} = \lim_{{x \to -3^+}} 2 = 2

  6. Conclusion: Since the left-hand limit is 2-2 and the right-hand limit is 22, the limit does not exist because the left and right limits are not equal.

Final Answer:

limx32x+6x+3 does not exist.\lim_{{x \to -3}} \frac{|2x + 6|}{x + 3} \text{ does not exist.}

Would you like more details or further clarification?


Here are five related questions to expand your understanding:

  1. What is the geometric interpretation of a limit that does not exist?
  2. How does absolute value affect the behavior of functions near critical points?
  3. How do left-hand and right-hand limits relate to the overall limit?
  4. What are some strategies for solving limits involving piecewise functions?
  5. How can you use graphical methods to determine if a limit exists?

Tip: Always check the left-hand and right-hand limits separately when dealing with absolute value expressions or discontinuities!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Limits
Piecewise Functions
Absolute Value

Formulas

|a| = a if a ≥ 0, |a| = -a if a < 0

Theorems

Left-hand limit and right-hand limit theorem
Limits involving absolute values

Suitable Grade Level

Grades 11-12