Math Problem Statement

Evaluate the limit: lim_{x -> 0} x / ( (1/(2 + x)) - (1/2) )

Solution

Let's evaluate the given limit expression step by step. The expression is:

limx0x12+x12\lim_{{x \to 0}} \frac{x}{{\frac{1}{{2 + x}} - \frac{1}{2}}}

Step 1: Simplify the denominator

The denominator is a difference of two fractions, 12+x12\frac{1}{{2 + x}} - \frac{1}{2}. To subtract these fractions, we need to find a common denominator:

12+x12=2(2+x)2(2+x)=22x2(2+x)=x2(2+x)\frac{1}{{2 + x}} - \frac{1}{2} = \frac{2 - (2 + x)}{2(2 + x)} = \frac{2 - 2 - x}{2(2 + x)} = \frac{-x}{2(2 + x)}

So, the expression becomes:

limx0xx2(2+x)\lim_{{x \to 0}} \frac{x}{\frac{-x}{2(2 + x)}}

Step 2: Simplify the fraction

Now, simplify the complex fraction by multiplying xx by the reciprocal of x2(2+x)\frac{-x}{2(2 + x)}:

xx2(2+x)=x2(2+x)x=2(2+x)1=2(2+x)\frac{x}{\frac{-x}{2(2 + x)}} = x \cdot \frac{2(2 + x)}{-x} = \frac{2(2 + x)}{-1} = -2(2 + x)

Step 3: Evaluate the limit

Now, take the limit as xx approaches 0:

limx02(2+x)=2(2+0)=4\lim_{{x \to 0}} -2(2 + x) = -2(2 + 0) = -4

Thus, the correct value of the limit is:

4\boxed{-4}

The correct answer is 4-4, not 14\frac{1}{4}.


Would you like any further explanation or more details?

Here are 5 related questions for further practice:

  1. What is the limit of limx0xx+1\lim_{{x \to 0}} \frac{x}{{x + 1}}?
  2. How would you evaluate limx0x(x2+1)1\lim_{{x \to 0}} \frac{x}{{(x^2 + 1) - 1}}?
  3. Can you solve limx0sin(x)x\lim_{{x \to 0}} \frac{\sin(x)}{x}?
  4. How do you handle indeterminate forms when evaluating limits?
  5. What is the limit of limx11cos(x)x1\lim_{{x \to 1}} \frac{1 - \cos(x)}{x - 1}?

Tip: Always simplify the expression as much as possible before applying the limit, and check for indeterminate forms like 00\frac{0}{0} where you might need additional techniques such as factoring or L'Hopital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Algebra
Simplifying Fractions

Formulas

Limit formula
Simplification of fractions
Subtraction of fractions

Theorems

Limit Theorem
Indeterminate Forms (0/0)

Suitable Grade Level

College-level calculus