Math Problem Statement

Starting with x = 5, use the iterative process to find an approximate solution to x^3 - 5x^2 - 11 = 0. Give your answer to 2 decimal places.

Solution

This problem uses an iterative process to approximate a solution to the equation x35x211=0x^3 - 5x^2 - 11 = 0 to two decimal places (2 d.p.). The steps involve the following process:

  1. Start with an initial value of x=5x = 5.
  2. Use the formula x=5+11x2x = 5 + \frac{11}{x^2}.
  3. Calculate the new xx, round it to 2 d.p., and compare it with the previous xx. If they match, the solution is found. Otherwise, repeat using the updated xx.

Let me work through this step-by-step to find the approximate solution:


Step 1: Start with x=5x = 5.

Step 2: Compute 5+11x25 + \frac{11}{x^2} with x=5x = 5.

x=5+1152=5+1125=5+0.44=5.44x = 5 + \frac{11}{5^2} = 5 + \frac{11}{25} = 5 + 0.44 = 5.44

Step 3: Round to 2 d.p. and compare.

  • Rounded x=5.44x = 5.44.
  • Since this does not match the initial x=5.00x = 5.00, repeat the process using x=5.44x = 5.44.

Next Iteration (using x=5.44x = 5.44):

Step 2: Compute 5+11x25 + \frac{11}{x^2} with x=5.44x = 5.44.

x=5+11(5.44)2x = 5 + \frac{11}{(5.44)^2} First, calculate 5.442=29.59365.44^2 = 29.5936, x=5+1129.5936=5+0.3716=5.3716x = 5 + \frac{11}{29.5936} = 5 + 0.3716 = 5.3716

Step 3: Round to 2 d.p. and compare.

  • Rounded x=5.37x = 5.37.
  • Since this does not match the previous x=5.44x = 5.44, repeat using x=5.37x = 5.37.

Next Iteration (using x=5.37x = 5.37):

Step 2: Compute 5+11x25 + \frac{11}{x^2} with x=5.37x = 5.37.

x=5+11(5.37)2x = 5 + \frac{11}{(5.37)^2} First, calculate 5.372=28.83695.37^2 = 28.8369, x=5+1128.8369=5+0.3815=5.3815x = 5 + \frac{11}{28.8369} = 5 + 0.3815 = 5.3815

Step 3: Round to 2 d.p. and compare.

  • Rounded x=5.38x = 5.38.
  • Since this does not match the previous x=5.37x = 5.37, repeat using x=5.38x = 5.38.

Next Iteration (using x=5.38x = 5.38):

Step 2: Compute 5+11x25 + \frac{11}{x^2} with x=5.38x = 5.38.

x=5+11(5.38)2x = 5 + \frac{11}{(5.38)^2} First, calculate 5.382=28.94445.38^2 = 28.9444, x=5+1128.9444=5+0.3801=5.3801x = 5 + \frac{11}{28.9444} = 5 + 0.3801 = 5.3801

Step 3: Round to 2 d.p. and compare.

  • Rounded x=5.38x = 5.38.
  • Since this matches the previous x=5.38x = 5.38, the process stops.

Final Answer:

The approximate solution to x35x211=0x^3 - 5x^2 - 11 = 0 is x=5.38x = 5.38 to 2 d.p.


Would you like me to verify this solution or explain any specific step further?

Here are some related questions to expand on:

  1. How does the iterative process converge to a solution?
  2. Can this method fail for certain equations or initial values?
  3. How can we verify if x=5.38x = 5.38 is indeed a solution to the given equation?
  4. What is the geometric interpretation of this iterative method?
  5. Are there alternative methods to solve this equation?

Tip: Iterative methods often rely on choosing a good initial value to ensure convergence to the correct solution!

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Math Problem Analysis

Mathematical Concepts

Iterative Methods
Approximation Techniques
Algebraic Equations

Formulas

x = 5 + 11 / x^2

Theorems

Fixed-Point Iteration

Suitable Grade Level

Grades 10-12