Math Problem Statement

For the function f(x) = x^3 + x - 2, write Newton's formula as x_{n+1} = F(x_n) = x_n - [f(x_n) / f'(x_n)] for solving f(x) = 0. Type in x_n for x_n.

Solution

To apply Newton's method for the function f(x)=x3+x2f(x) = x^3 + x - 2, we first need to find its derivative f(x)f'(x).

  1. Function: f(x)=x3+x2f(x) = x^3 + x - 2

  2. Derivative: Differentiate f(x)f(x) with respect to xx.

    f(x)=3x2+1f'(x) = 3x^2 + 1

Newton's formula for finding the next approximation xn+1x_{n+1} is:

xn+1=xnf(xn)f(xn)x_{n+1} = x_n - \frac{f(x_n)}{f'(x_n)}

Substitute f(xn)f(x_n) and f(xn)f'(x_n):

xn+1=xnxn3+xn23xn2+1x_{n+1} = x_n - \frac{x_n^3 + x_n - 2}{3x_n^2 + 1}

Thus, the answer is:

xn+1=xnxn3+xn23xn2+1x_{n+1} = x_n - \frac{x_n^3 + x_n - 2}{3x_n^2 + 1}

Would you like further details or have any questions?

Here are some related questions that could help deepen your understanding:

  1. How does Newton's method work to approximate roots of functions?
  2. Why is the derivative important in Newton's method?
  3. What are the potential limitations of Newton's method?
  4. Can Newton's method fail, and if so, under what conditions?
  5. How would Newton’s method apply to a different function, such as f(x)=ex2xf(x) = e^x - 2x?

Tip: Newton's method converges quickly when the initial guess is close to the actual root, but it may diverge if the initial guess is far or if the function's derivative is zero at any step.

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Math Problem Analysis

Mathematical Concepts

Calculus
Root-Finding Algorithms

Formulas

Newton's Method: x_{n+1} = x_n - (f(x_n) / f'(x_n))
Derivative of f(x) = x^3 + x - 2: f'(x) = 3x^2 + 1

Theorems

Newton's Method for Approximating Roots

Suitable Grade Level

Undergraduate or Advanced High School (Grades 11-12)