Math Problem Statement

limx2x+52xsinx\lim_{x\to2}\frac{x+5}{\left|2-x\right|}\sin x

Solution

To evaluate the limit

limx2x+52xsinx,\lim_{x \to 2} \frac{x+5}{|2 - x|} \sin x,

we'll analyze it carefully.

Step 1: Separate the expressions

We can break the given expression into separate parts:

f(x)=x+52xsinxf(x) = \frac{x+5}{|2 - x|} \sin x

where we will handle the behavior of each factor as x2x \to 2.

  • The term x+5x + 5 is continuous, so as x2x \to 2, we have:

    limx2(x+5)=7\lim_{x \to 2} (x + 5) = 7

  • The term sinx\sin x is also continuous, and as x2x \to 2, we get:

    limx2sinx=sin(2)0.9093\lim_{x \to 2} \sin x = \sin(2) \approx 0.9093

Step 2: Handle the absolute value

The absolute value function 2x|2 - x| behaves differently depending on whether xx approaches 2 from the left (x2x \to 2^-) or from the right (x2+x \to 2^+).

  • If x2+x \to 2^+, then 2x=x2|2 - x| = x - 2, which approaches 0 from the positive side.
  • If x2x \to 2^-, then 2x=2x|2 - x| = 2 - x, which also approaches 0 but from the positive side.

In both cases, 2x0+|2 - x| \to 0^+ as x2x \to 2, and thus the term x+52x\frac{x + 5}{|2 - x|} becomes unbounded.

Step 3: Analyze the overall limit

  • As x2x \to 2, the term x+52x\frac{x+5}{|2-x|} blows up to infinity (approaching ++\infty).
  • Meanwhile, sin(2)\sin(2) remains finite.

Thus, the entire expression behaves like ×finite\infty \times \text{finite}, and the limit tends to infinity.

Conclusion:

The limit does not exist in a finite sense; instead, the limit tends to infinity:

limx2x+52xsinx=+.\lim_{x \to 2} \frac{x+5}{|2 - x|} \sin x = +\infty.

Would you like more details on any step?


Here are five related questions to extend your understanding:

  1. What are the properties of the absolute value function in limits?
  2. How does the behavior of 12x\frac{1}{|2-x|} change when x2x \to 2?
  3. What happens if we replace sinx\sin x with a different trigonometric function?
  4. How do we approach limits involving absolute value functions and discontinuities?
  5. Can you evaluate limx2x+52xsinx\lim_{x \to 2} \frac{x+5}{2-x} \sin x without the absolute value?

Tip: When evaluating limits involving absolute values, always consider the left- and right-hand behaviors of the function separately!

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Math Problem Analysis

Mathematical Concepts

Limits
Trigonometry
Absolute Value
Continuity

Formulas

lim_{x\to 2} (x + 5) = 7
lim_{x\to 2} \sin x = \sin(2)
|2 - x| as x approaches 2
Unbounded behavior of \frac{x+5}{|2 - x|}

Theorems

Limit definition
Properties of the absolute value function
Behavior of continuous functions

Suitable Grade Level

Grades 11-12 (Pre-Calculus/Calculus)