Lesson 253

Numerical Methods & Stability

Round-off · Root-finding · Stability

1:00

Why computers cannot do exact real-number arithmetic, and the core methods — bisection, Newton, integration rules, and Gaussian pivoting — that keep floating-point errors under control.

By the end, you can

  • Explain why 0.1 + 0.2 is not exactly 0.3 in IEEE-754 floating point.
  • Distinguish round-off error from truncation error and identify which source each arises from.
  • Recognize catastrophic cancellation and describe how to avoid it.
  • Define condition number and stability, and explain why they are separate concepts.
  • Trace two steps of bisection on a given bracket and state its convergence rate.
  • Apply one Newton iteration given the update rule and state its convergence rate.
  • Compare the error orders of the trapezoidal rule and Simpson's rule and compute the improvement from refinement.
  • Explain why partial pivoting is the standard stable default for Gaussian elimination.
Up next in Advanced Algorithms, Math & PL Theory
Questions or feedback?