Math Problem Statement

Evaluate \( \lim_{x \to 1} \frac{\sqrt{x} - 1}{x - 1} \).

Solution

The mathematical expression in the image appears to be:

limx1x1x1.\lim_{x \to 1} \frac{\sqrt{x} - 1}{x - 1}.

Let me solve this step-by-step:

Step 1: Check for indeterminate form

Substituting x=1x = 1 directly: 1111=00.\frac{\sqrt{1} - 1}{1 - 1} = \frac{0}{0}. This is an indeterminate form, so we need to simplify further.

Step 2: Simplify using algebraic manipulation

The numerator x1\sqrt{x} - 1 can be rationalized: x1x1x+1x+1=(x1)(x+1)(x1)(x+1).\frac{\sqrt{x} - 1}{x - 1} \cdot \frac{\sqrt{x} + 1}{\sqrt{x} + 1} = \frac{(\sqrt{x} - 1)(\sqrt{x} + 1)}{(x - 1)(\sqrt{x} + 1)}.

In the numerator, we expand: (x1)(x+1)=x1.(\sqrt{x} - 1)(\sqrt{x} + 1) = x - 1.

Thus, the expression simplifies to: x1(x1)(x+1)=1x+1,x1.\frac{x - 1}{(x - 1)(\sqrt{x} + 1)} = \frac{1}{\sqrt{x} + 1}, \quad x \neq 1.

Step 3: Evaluate the limit

Now substitute x=1x = 1 into the simplified expression: 11+1=11+1=12.\frac{1}{\sqrt{1} + 1} = \frac{1}{1 + 1} = \frac{1}{2}.

Final Answer:

limx1x1x1=12.\lim_{x \to 1} \frac{\sqrt{x} - 1}{x - 1} = \frac{1}{2}.

Let me know if you'd like more details or clarifications. Here are 5 related questions for practice:

  1. How do you rationalize the numerator of a fraction involving square roots?
  2. What are other methods to solve indeterminate forms like 00\frac{0}{0}?
  3. How does the concept of limits apply to functions with radicals?
  4. What is L'Hôpital's Rule, and could it be used here?
  5. How can you check if a function is continuous at a given point?

Tip: When solving limits, always check if simplifying the expression or rationalizing helps before applying advanced techniques like L'Hôpital's Rule!

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Math Problem Analysis

Mathematical Concepts

Limits
Rationalization
Algebraic Simplification

Formulas

Rationalization: \( (\sqrt{a} - b)(\sqrt{a} + b) = a - b^2 \)
Limit Definition: \( \lim_{x \to c} f(x) \)

Theorems

Limit Simplification Techniques

Suitable Grade Level

Grades 11-12