Math Problem Statement

Suppose we want to approximate the value of 63^(1/3) using a Taylor polynomial.

Solution

The problem provided asks to approximate 631/363^{1/3} using a Taylor polynomial.

Let's break it down step-by-step:

(a) Determine an appropriate power function f(x)f(x):

To approximate 631/363^{1/3}, we can choose the function f(x)=x1/3f(x) = x^{1/3}. This function gives the cube root of xx, which directly applies to the given expression.

(b) What would be an appropriate basepoint aa?

To find a basepoint aa, we want to select a value near 63 for which we can easily compute the cube root. A good choice is a=64a = 64, because 641/3=464^{1/3} = 4. This makes calculations simpler and keeps the approximation close to the target value.

(c) Find T1(x)T_1(x):

The first-degree Taylor polynomial T1(x)T_1(x) around x=ax = a is given by: T1(x)=f(a)+f(a)(xa)T_1(x) = f(a) + f'(a)(x - a) For f(x)=x1/3f(x) = x^{1/3}, we first compute f(x)f'(x): f(x)=13x2/3f'(x) = \frac{1}{3}x^{-2/3} Now, using a=64a = 64: f(64)=641/3=4f(64) = 64^{1/3} = 4 f(64)=13642/3=13116=148f'(64) = \frac{1}{3} \cdot 64^{-2/3} = \frac{1}{3} \cdot \frac{1}{16} = \frac{1}{48} Thus, the first-degree Taylor polynomial is: T1(x)=4+148(x64)T_1(x) = 4 + \frac{1}{48}(x - 64)

(d) Use T1(x)T_1(x) to estimate the value of 631/363^{1/3}:

Now, substitute x=63x = 63 into the Taylor polynomial T1(x)T_1(x): T1(63)=4+148(6364)=4+148(1)=4148=40.02083=3.97917T_1(63) = 4 + \frac{1}{48}(63 - 64) = 4 + \frac{1}{48}(-1) = 4 - \frac{1}{48} = 4 - 0.02083 = 3.97917 Thus, the estimated value of 631/363^{1/3} is approximately 3.979173.97917.

Would you like more details on any of the steps or further clarifications?

Here are 5 questions that extend the discussion:

  1. How can the accuracy of this approximation be improved with higher-order terms?
  2. What is the general formula for the nn-th derivative of f(x)=x1/3f(x) = x^{1/3}?
  3. Why is a=64a = 64 a better choice than a=60a = 60 or a=65a = 65 for this approximation?
  4. How would the approximation differ if you used a second-degree Taylor polynomial?
  5. Can this method be used to approximate other roots, like 631/563^{1/5}?

Tip: When using Taylor polynomials, selecting a basepoint aa close to the value you're approximating improves the accuracy of the approximation!

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Math Problem Analysis

Mathematical Concepts

Taylor Polynomial
Cube Root Approximation
Derivative

Formulas

f(x) = x^(1/3)
T_1(x) = f(a) + f'(a)(x - a)
f'(x) = (1/3)x^(-2/3)

Theorems

Taylor's Theorem

Suitable Grade Level

Grades 11-12 (Pre-Calculus/Calculus)