Pi (letter)
From Free net encyclopedia
| [[Image:Greek alphabet {{{letter|alpha-omega}}}.png| 200px|center]] | |
| Greek alphabet | |
|---|---|
| Α α Alpha | Β β Beta |
| Γ γ Gamma | Δ δ Delta |
| Ε ε Epsilon | Ζ ζ Zeta |
| Η η Eta | Θ θ Theta |
| Ι ι Iota | Κ κ Kappa |
| Λ λ Lambda | Μ μ Mu |
| Ν ν Nu | Ξ ξ Xi |
| Ο ο Omicron | Π π Pi |
| Ρ ρ Rho | Σ σ ς Sigma |
| Τ τ Tau | Υ υ Upsilon |
| Φ φ Phi | Χ χ Chi |
| Ψ ψ Psi | Ω ω Omega |
| obsolete letters | |
| Image:Greek alphabet digamma2.png Digamma | Image:Greek alphabet san.png San |
| Image:Greek alphabet qoppa.png Qoppa | Image:Greek alphabet sampi.png Sampi |
| Image:Greek alphabet stigma.png Stigma | Image:Greek alphabet sho.png Sho |
- For other uses, see Pi (disambiguation)
Pi (upper case Π, lower case π or ϖ) is the sixteenth letter of the Greek alphabet. In the system of Greek numerals it has a value of 80.
In Greek, the letter is pronounced Template:IPA (as in pee); in modern English, it is pronounced Template:IPA (as the word pie), in particular when referring to the mathematical constant (see below). In words, it is pronounced Template:IPA. In Modern Greek, the sequence of letters μπ represents the Template:IPA sound, as in boy (the second letter of the Greek alphabet is now pronounced Template:IPA as in very).
There is another variant of lower case Pi, resembling a lower case Omega: <math>\varpi\,\!</math>.
The upper-case letter Π is used as a symbol for:
- The product operator in mathematics (in analogy to the use of the capital Sigma Σ as summation symbol).
- In textual criticism, Codex Petropolitanus, a 9th century, uncial codex of the Gospels, now located in St. Petersburg, Russia.
The lower-case letter π is used as a symbol for:
- The mathematical irrational constant π ≈ 3.14159..., the ratio of a circle's circumference to its diameter in Euclidean geometry.
- The prime counting function in mathematics.
- Dimensionless parameters constructed using the Buckingham π theorem of dimensional analysis.
- The elementary particle called the pi meson or pion.
- Profit in microeconomics.
- Inflation rate in macroeconomics.
- A type of chemical bond in which the P-orbitals overlap
In HTML, the capital letter Π can be produced using the codes Π or Π, and the lower-case by using π or π within the source code.als:Π bg:Пи (буква) ca:Π da:Pi (bogstav) de:Pi el:Πι es:Π fr:Pi (lettre grecque) ko:Π he:פאי (אות) nl:Pi (letter) nds:Pi ja:Π nn:Π pl:Pi (litera) pt:Π sk:Pí (písmeno) sv:Pi (bokstav) zh:Π