What it means
The fourth Greek letter. Capital Δ means a change in a quantity: Δx is the change in x. Lower-case δ is a small change or variation, the Kronecker delta δᵢⱼ (1 when i equals j, otherwise 0), the Dirac delta function and, with ε, the small numbers in the definition of a limit.
Read aloud in real formulas
v = Δx / Δt
Aethel says
v equals delta x over delta t
average velocity: change in position over change in time
δᵢⱼ = 1
Aethel says
delta sub i j equals 1
the Kronecker delta when i = j
Δx Δp ≥ ħ/2
Aethel says
delta x delta p is greater than or equal to h bar over 2
uncertainties in position and momentum
Typing it
- LaTeX
- \delta, \Delta
- Unicode
- U+03B4, U+0394
Formulas that use it
Questions
How do you pronounce delta (δ)?
It is said “delta”, roughly DEL-tuh.
What does δ mean in maths?
The fourth Greek letter. Capital Δ means a change in a quantity: Δx is the change in x. Lower-case δ is a small change or variation, the Kronecker delta δᵢⱼ (1 when i equals j, otherwise 0), the Dirac delta function and, with ε, the small numbers in the definition of a limit.
How do you type δ?
In LaTeX, write \delta, \Delta. Its Unicode code point is U+03B4, U+0394.
What is δ often confused with?
It is easy to mistake for ∂ (the partial derivative sign) and ∇ (nabla, an upside-down Δ).