Math Problem Statement

obtain the taylors series of fx= x power 1/3 up to the term x power 2 at a=8

Solution

To find the Taylor series of f(x)=x1/3f(x) = x^{1/3} about a=8a = 8, we use the formula for the Taylor series expansion:

f(x)=n=0f(n)(a)n!(xa)nf(x) = \sum_{n=0}^{\infty} \frac{f^{(n)}(a)}{n!} (x - a)^n

Step 1: Compute the derivatives of f(x)=x1/3f(x) = x^{1/3}.

  1. First derivative f(x)f'(x): f(x)=13x2/3f'(x) = \frac{1}{3}x^{-2/3}

  2. Second derivative f(x)f''(x): f(x)=29x5/3f''(x) = -\frac{2}{9}x^{-5/3}

  3. Third derivative f(3)(x)f^{(3)}(x): f(3)(x)=1027x8/3f^{(3)}(x) = \frac{10}{27}x^{-8/3}

Step 2: Evaluate the function and derivatives at x=8x = 8.

  1. Evaluate f(8)f(8): f(8)=81/3=2f(8) = 8^{1/3} = 2

  2. Evaluate f(8)f'(8): f(8)=1382/3=1314=112f'(8) = \frac{1}{3} \cdot 8^{-2/3} = \frac{1}{3} \cdot \frac{1}{4} = \frac{1}{12}

  3. Evaluate f(8)f''(8): f(8)=2985/3=29132=1144f''(8) = -\frac{2}{9} \cdot 8^{-5/3} = -\frac{2}{9} \cdot \frac{1}{32} = -\frac{1}{144}

  4. Evaluate f(3)(8)f^{(3)}(8): f(3)(8)=102788/3=10271256=106912f^{(3)}(8) = \frac{10}{27} \cdot 8^{-8/3} = \frac{10}{27} \cdot \frac{1}{256} = \frac{10}{6912}

Step 3: Write out the Taylor series up to (x8)2(x - 8)^2.

The Taylor series expansion is:

f(x)f(8)+f(8)(x8)+f(8)2!(x8)2f(x) \approx f(8) + f'(8)(x - 8) + \frac{f''(8)}{2!}(x - 8)^2

Substitute the values we calculated:

f(x)2+112(x8)1144(x8)22f(x) \approx 2 + \frac{1}{12}(x - 8) - \frac{1}{144} \cdot \frac{(x - 8)^2}{2}

Simplifying:

f(x)2+112(x8)1288(x8)2f(x) \approx 2 + \frac{1}{12}(x - 8) - \frac{1}{288}(x - 8)^2

This is the Taylor series of f(x)=x1/3f(x) = x^{1/3} about x=8x = 8 up to the (x8)2(x - 8)^2 term.

Would you like any further clarification or more detailed steps?

Follow-up Questions:

  1. What would the next term in the series be if we included the third derivative?
  2. How would the series change if we expanded around a different value of aa?
  3. How does the accuracy of the approximation depend on the number of terms in the Taylor series?
  4. Could this series be used to approximate cube roots for values near x=8x = 8?
  5. What is the geometric interpretation of the Taylor series approximation?

Tip:

When expanding functions using Taylor series, it's helpful to calculate a few higher-order derivatives, even if they're not immediately used, as they can show how quickly the series converges.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Taylor Series
Derivatives
Polynomial Approximation

Formulas

f(x) ≈ Σ (f^n(a)/n!) * (x - a)^n
f(x) = x^(1/3)
First, Second, and Third Derivatives of f(x)

Theorems

Taylor's Theorem

Suitable Grade Level

Undergraduate Calculus (Grade 12 and above)