Iterative methods

Understanding Iterative Methods

  • Iterative methods are a type of calculation technique used to find approximate solutions for algebraic equations.
  • These methods use a process of prediction and refinement to converge on a more accurate answer.
  • The iterative formula gets applied repeatedly, each time using the result of the previous iteration, hence the name “iterative”.

Description of Iterative Methods

  • Iterative methods start with an initial guess of the root (solution) of the equation, this is often referred to as x0 (x-naught).
  • This initial guess gets substituted into the iterative formula to produce the next approximation, x1.
  • The value of x1 is then used to find x2, and so on, creating a sequence of values which we hope will get closer and closer to the root of the equation.
  • However, success is not guaranteed. How well (or if) iterative methods work depends on both the function and the chosen initial guess.

Rearranging Equations in Iterative Methods

  • Iterative methods often require equations to be rearranged into an appropriate format.
  • For example, the equation x³ + x = 15 could be rearranged to x = ∛(15 - x) for use in an iterative method.
  • It’s important to remember that different rearrangements might lead to different sequences and results.

Evaluating the Efficiency of Iterative Methods

  • The utility of an iterative method is often determined by how fast it converges to the root, and how reliable the method is.
  • The rate of convergence is sometimes evaluated by looking at the difference between successive iterations.
  • Always cross-check the final iteration with the original equation to ensure the solution is correct.

Important Tips

  • Be familiar with multiple iterations and understand when it is beneficial to stop iterating.
  • Understanding the graph of a function could aid in selecting a good initial guess for the root.
  • Always state the iteration formula clearly and make sure to provide steps of calculation.
  • Precision in calculation is key, avoid rounding off values during the iteration steps.
  • Practice different types of equations to understand how the iterative formula changes depending on the situation.