Delta
lastmod 2020-10-17created 2015-12-223 edits
Δ, δ (delta) is the fourth letter of the Greek alphabet, and in Greek numerals it means 4. The Latin letter D and the Cyrillic letter Д derive from it.
Uses
Δ means the following.
- In mathematics:
- A symbol denoting a difference of values
- A symbol denoting the Laplace operator
- A symbol denoting the discriminant
δ means the following.
- In mathematics, a symbol denoting a small difference of values
- Dirac delta function
- In astronomy, a symbol denoting declination
∂ means the following.
- Mainly used as the mathematical symbol for the partial derivative, in expressions like \(\frac{\partial z}{\partial x}\) (read "the partial derivative of z with respect to x").
Upper case
The upper-case letter Δ can be used to denote:
- Change of any changeable quantity, in mathematics and the sciences (more specifically, the difference operator); for example, in:
\[ {y_2-y_1\over x_2-x_1} = {\Delta y \over \Delta x} , \]
- the average change of y per unit x (i.e. the change of y over the change of x). Delta is the initial letter of the Greek word διαφορά diaphorá, "difference". (The small Latin letter d is used in much the same way for the notation of derivatives and differentials, which also describe change.)