Math Problem Statement

solve

Solution

Let's analyze the problem step by step.

Given Function:

f(x)=x2x+3f(x) = \frac{x}{2x+3}

Part (a): Find the first Taylor polynomial P1(x)P_1(x) of f(x)f(x) at x=0x = 0.

The Taylor series expansion of a function f(x)f(x) around x=ax = a is given by: f(x)=f(a)+f(a)(xa)+f(a)2!(xa)2+f(x) = f(a) + f'(a)(x - a) + \frac{f''(a)}{2!}(x - a)^2 + \dots

Since we are looking for the first Taylor polynomial P1(x)P_1(x), we only need the first two terms of the series: P1(x)=f(0)+f(0)xP_1(x) = f(0) + f'(0)x

  1. Find f(0)f(0): f(0)=02(0)+3=0f(0) = \frac{0}{2(0) + 3} = 0

  2. Find f(x)f'(x): Use the quotient rule: f(x)=(2x+3)(1)x(2)(2x+3)2=2x+32x(2x+3)2=3(2x+3)2f'(x) = \frac{(2x + 3)(1) - x(2)}{(2x + 3)^2} = \frac{2x + 3 - 2x}{(2x + 3)^2} = \frac{3}{(2x + 3)^2} Now evaluate f(0)f'(0): f(0)=3(2(0)+3)2=39=13f'(0) = \frac{3}{(2(0) + 3)^2} = \frac{3}{9} = \frac{1}{3}

Thus, the first Taylor polynomial is: P1(x)=0+13x=13xP_1(x) = 0 + \frac{1}{3}x = \frac{1}{3}x

Part (b): Use the Taylor polynomial to approximate f(1.05)f(1.05).

Now, approximate f(1.05)f(1.05) using P1(x)P_1(x): P1(1.05)=13×1.05=1.0530.35P_1(1.05) = \frac{1}{3} \times 1.05 = \frac{1.05}{3} \approx 0.35

Part (c): Calculate the error in the Taylor series approximation, f(1.05)P1(1.05)|f(1.05) - P_1(1.05)|, to 4 decimal places.

  1. Calculate f(1.05)f(1.05): f(1.05)=1.052(1.05)+3=1.052.1+3=1.055.10.2059f(1.05) = \frac{1.05}{2(1.05) + 3} = \frac{1.05}{2.1 + 3} = \frac{1.05}{5.1} \approx 0.2059

  2. Calculate the error: Error=f(1.05)P1(1.05)=0.20590.35=0.1441\text{Error} = |f(1.05) - P_1(1.05)| = |0.2059 - 0.35| = 0.1441

So, the error is approximately 0.1441.

Would you like any further details or explanations on these calculations?

Here are five related questions:

  1. What is the second-degree Taylor polynomial P2(x)P_2(x) for f(x)f(x) at x=0x = 0?
  2. How does the error change if you use the second-degree polynomial instead of the first-degree polynomial?
  3. What is the radius of convergence for the Taylor series of f(x)f(x) around x=0x = 0?
  4. How would the Taylor polynomial change if you expanded around x=1x = 1 instead of x=0x = 0?
  5. How does the Taylor series help in approximating functions that are difficult to evaluate directly?

Tip: Remember that the error in a Taylor series approximation depends on the number of terms used. The more terms you include, the smaller the error, especially near the point of expansion.

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Math Problem Analysis

Mathematical Concepts

Calculus
Taylor series
Taylor polynomial

Formulas

Taylor series expansion
Quotient rule

Theorems

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Suitable Grade Level

Advanced Undergraduate