Math Problem Statement

solve this with newton for x0=0.1, 0.7 and 0.9 x.e^(x^2)-1=0

Solution

We are tasked with solving the equation xex21=0x \cdot e^{x^2} - 1 = 0 using Newton's method with different initial guesses for x0=0.1,0.7,x_0 = 0.1, 0.7, and 0.90.9.

Newton's Method Formula:

Newton's method is an iterative method used to approximate roots of a real-valued function. The formula for 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)}

Where:

  • f(x)f(x) is the function we want to solve.
  • f(x)f'(x) is the derivative of f(x)f(x).
  • xnx_n is the current approximation, and xn+1x_{n+1} is the next approximation.

Step 1: Define the Function and its Derivative

The function we want to solve is:

f(x)=xex21f(x) = x \cdot e^{x^2} - 1

To apply Newton's method, we need to compute its derivative f(x)f'(x).

Function:

f(x)=xex21f(x) = x \cdot e^{x^2} - 1

Derivative of the Function:

Using the product rule and chain rule for differentiation:

f(x)=ddx(xex2)=ex2+2x2ex2f'(x) = \frac{d}{dx} \left( x \cdot e^{x^2} \right) = e^{x^2} + 2x^2 \cdot e^{x^2} Thus, f(x)=ex2(1+2x2)f'(x) = e^{x^2} (1 + 2x^2)

Step 2: Apply Newton's Method

We will use the following iterative formula: xn+1=xnxnexn21exn2(1+2xn2)x_{n+1} = x_n - \frac{x_n \cdot e^{x_n^2} - 1}{e^{x_n^2} (1 + 2x_n^2)}

Now, I will calculate the approximations for x0=0.1x_0 = 0.1, x0=0.7x_0 = 0.7, and x0=0.9x_0 = 0.9 using this formula.

Let me perform the calculations.The solutions obtained using Newton's method for the equation xex21=0x \cdot e^{x^2} - 1 = 0 with the different initial guesses are as follows:

  • For x0=0.1x_0 = 0.1, the root is approximately 0.652920.65292 after 5 iterations.
  • For x0=0.7x_0 = 0.7, the root is approximately 0.652920.65292 after 3 iterations.
  • For x0=0.9x_0 = 0.9, the root is approximately 0.652920.65292 after 4 iterations.

In each case, the method converged to the same root x0.65292x \approx 0.65292.

Do you need more details or have any questions?

Here are 5 related questions for further practice:

  1. What happens if the initial guess is far from the root in Newton's method?
  2. How does the choice of tolerance affect the accuracy and speed of convergence in Newton's method?
  3. What is the significance of the derivative f(x)f'(x) in determining the convergence of Newton's method?
  4. Can Newton's method fail to converge, and under what circumstances?
  5. How does Newton's method compare to other root-finding methods like the bisection method?

Tip: When using Newton's method, choosing a good initial guess can significantly reduce the number of iterations required for convergence.

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Math Problem Analysis

Mathematical Concepts

Numerical Methods
Calculus
Exponential Functions

Formulas

Newton's method: x_{n+1} = x_n - f(x_n) / f'(x_n)
f(x) = x * e^{x^2} - 1
f'(x) = e^{x^2} * (1 + 2x^2)

Theorems

Newton's Method
Chain Rule of Differentiation
Product Rule of Differentiation

Suitable Grade Level

Undergraduate (Numerical Methods or Calculus courses)