Math Problem Statement

Round to four decimal places

Complete the table and estimate the limit of the function \(\lim_{x \to 4} \frac{\frac{1}{x+1} - \frac{1}{5}}{x - 4}\) rounding to four decimal places.

Solution

To solve this, we need to compute the values of the function given by:

f(x)=1x+115x4f(x) = \frac{\frac{1}{x+1} - \frac{1}{5}}{x - 4}

Step 1: Analyze the function

This is a difference quotient, which can be simplified and evaluated for different values of xx near 4 to estimate the limit. First, let's simplify the numerator:

1x+115=5(x+1)5(x+1)=4x5(x+1)\frac{1}{x+1} - \frac{1}{5} = \frac{5 - (x+1)}{5(x+1)} = \frac{4 - x}{5(x+1)}

Thus, the function becomes:

f(x)=4x5(x+1)x4=4x5(x+1)(x4)f(x) = \frac{\frac{4 - x}{5(x+1)}}{x - 4} = \frac{4 - x}{5(x+1)(x - 4)}

This can further be simplified to:

f(x)=15(x+1)f(x) = -\frac{1}{5(x+1)}

Step 2: Calculate the values of f(x)f(x) for different xx

Now we compute the values of f(x)f(x) for the provided values of xx in the table: x=3.9,3.99,3.999,4.001,4.01,4.1x = 3.9, 3.99, 3.999, 4.001, 4.01, 4.1.

I'll calculate these values.Here are the computed values for f(x)f(x) at the given xx values, rounded to four decimal places:

  • f(3.9)=0.0408f(3.9) = -0.0408
  • f(3.99)=0.0401f(3.99) = -0.0401
  • f(3.999)=0.0400f(3.999) = -0.0400
  • f(4.001)=0.0400f(4.001) = -0.0400
  • f(4.01)=0.0399f(4.01) = -0.0399
  • f(4.1)=0.0392f(4.1) = -0.0392

Step 3: Estimate the limit

Looking at these values, as xx approaches 4 from both sides, the function seems to approach 0.04-0.04. Therefore, the estimated limit is:

limx41x+115x40.0400\lim_{x \to 4} \frac{\frac{1}{x+1} - \frac{1}{5}}{x - 4} \approx -0.0400

Would you like any further clarifications or detailed steps?

Here are some follow-up questions:

  1. How do we use limits to estimate values around a discontinuity?
  2. What are difference quotients and their role in calculus?
  3. Can we calculate limits of more complex functions using the same process?
  4. What is the significance of simplifying the function before evaluating the limit?
  5. How can graphing utilities help confirm limit estimates?

Tip: When dealing with limits, simplifying the function can often reveal the limit more clearly and make computations easier!

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Math Problem Analysis

Mathematical Concepts

Limits
Difference Quotients
Algebraic Simplification

Formulas

f(x) = \frac{\frac{1}{x+1} - \frac{1}{5}}{x - 4}

Theorems

Limit Theorem
Simplification

Suitable Grade Level

Grades 11-12