Equation 2 · Part 1 · How Mathematics, Proof, and Scientific Computation Actually Work
Symbol u
What this part means
the unit roundoff — roughly 10^{-16} for standard double precision — and is addition, subtraction, multiplication, or division.
Its job in the formula
u is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol u→Article meaning
Where the article explains it
where u is the unit roundoff — roughly 10^{-16} for standard double precision — and is addition, subtraction, multiplication, or division.
The passage around this formula
where u is the unit roundoff — roughly 10^{-16} for standard double precision — and is addition, subtraction, multiplication, or division. Each single step, in other words, is correct up to a tiny, precisely bounded relative error.
Learn the underlying idea
A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.
Open the illustrated variables: a letter stands for a value guide →
See this notation across published equations →
Sources cited in the article section
- [5] IEEE 754-2019 — IEEE Standard for Floating-Point Arithmetic ↗
- [6] Accuracy and Stability of Numerical Algorithms (2nd ed.) ↗
These citations provide research context; check each source for the exact claim it supports.