Delta (letter)
Delta is the fourth letter of the Greek alphabet. In the system of Greek numerals, it has a value of four. It was derived from the Phoenician letter dalet ?. Letters that come from delta include the Latin D and the Cyrillic Д.
A river delta is named so because its shape approximates the triangular uppercase letter delta. Contrary to a popular legend, this use of the word delta was not coined by Herodotus.
Pronunciation
In Ancient Greek, delta represented a voiced dental plosive. In Modern Greek, it represents a voiced dental fricative, like the "th" in "that", "this", or "though" . Delta is romanized as d or dh.Uppercase
The uppercase letter Δ is used to denote:- Change of any changeable quantity, in mathematics and the sciences ; for example, in, the average change of y per unit x. Delta is the initial letter of the Greek word διαφορά, diaphorá, "difference".
- The Laplace operator:
- :.
- The discriminant of a polynomial equation, especially the quadratic equation:
- :.
- The area of a triangle:
- :.
- The symmetric difference of two sets.
- A macroscopic change in the value of a variable in mathematics or science.
- Uncertainty in a physical variable as seen in the uncertainty principle.
- An interval of possible values for a given quantity.
- Any of the delta particles in particle physics.
- The determinant of the matrix of coefficients of a set of linear equations.
- That an associated locant number represents the location of a covalent bond in an organic compound, the position of which is variant between isomeric forms.
- A simplex, simplicial complex, or convex hull.
- In chemistry, the addition of heat in a reaction.
- In legal shorthand, it represents a defendant.
- In the financial markets, one of the Greeks, describes the rate of change of an option price for a given change in the underlying benchmark.
- A major seventh chord in jazz music notation.
- In genetics, it can stand for a gene deletion.
- The American Dental Association cites it as the symbol of dentistry.
- The anonymous signature of James David Forbes.
- Determinacy in philosophical logic.
- In mathematics, the symbol ≜ is occasionally used to define a new variable or function.
Lowercase
- A change in the value of a variable in calculus.
- A functional derivative in functional calculus.
- The -definition of limits, in mathematics and more specifically in calculus.
- The Kronecker delta in mathematics.
- The central difference for a function.
- The degree of a vertex in graph theory.
- The Dirac delta function in mathematics.
- The transition function in automata.
- Deflection in engineering mechanics.
- The force of interest in actuarial science.
- The chemical shift of nuclear magnetic resonance in chemistry.
- The relative electronegativity of different atoms in a molecule, δ− being more electronegative than δ+.
- Text requiring deletion in proofreading; the usage is said to date back to classical times.
- In some of the manuscripts written by Dr. John Dee, the character of delta is used to represent Dee.
- A subunit of the F1 sector of the F-ATPase.
- The declination of an object in the equatorial coordinate system of astronomy.
- The dividend yield in the Black–Scholes option pricing formula.
- Ratios of environmental isotopes, such as 18O/16O and D/1H from water are displayed using delta notation – δ18O and δD, respectively.
- The rate of depreciation of the aggregate capital stock of an economy in an exogenous growth model in macroeconomics.
- In a system that exhibits electrical reactance, the angle between voltage and current.
- Partial charge in chemistry.
- The maximum birefringence of a crystal in optical mineralogy.
- An Old Irish voiced dental or alveolar fricative of uncertain articulation, the ancestor of the sound represented by Modern Irish dh.
- Silver ratio
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