Zeroing In

Part of Iteration · Section 1 of 4

IntroductionUnit: AlgebraGCSE

This introduction covers Zeroing In within Iteration for GCSE Mathematics. Revise Iteration in Algebra for GCSE Mathematics with 9 exam-style questions and 3 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 1 of 4 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.

Zeroing In

Some equations can't be solved exactly. But we can get closer and closer to the answer by "iterating" - using each answer to calculate a better one. It's like zooming in on a target, getting more accurate each time.
Iteration method diagram

Practice questions for Iteration

What is the purpose of using an iterative formula in mathematics?

  • A. To find exact algebraic solutions to equations
  • B. To get increasingly accurate numerical approximations to solutions
  • C. To factorise quadratic expressions
  • D. To draw graphs of functions
1 markfoundation

A student uses the iterative formula xₙ₊₁ = xₙ² − 2 with x₀ = 0.5 and obtains the sequence 0.5, −1.75, 1.0625, −0.871, −1.241, ... Explain what is happening.

2 marksstandard

Quick recall flashcards

Sum Formula
S_n = a(r^n - 1)/(r - 1) where r is common ratio
Iteration Process
Put xₙ into formula to get xₙ₊₁. Repeat until values converge (settle down).

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