Root of unityIn mathematics, a root of unity, occasionally called a de Moivre number, is any complex number that yields 1 when raised to some positive integer power n. Roots of unity are used in many branches of mathematics, and are especially important in number theory, the theory of group characters, and the discrete Fourier transform. Roots of unity can be defined in any field. If the characteristic of the field is zero, the roots are complex numbers that are also algebraic integers.
General relativityGeneral relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime.
TI-BASICTI-BASIC is the official name of a BASIC-like language built into Texas Instruments (TI)'s graphing calculators. TI-BASIC is a language family of three different and incompatible versions, released on different products: TI-BASIC 83 (on Z80 processor) for TI-83 series, TI-84 Plus series TI-BASIC 89 (on 68k processor) for TI-89 series, TI-92 series, Voyage 200 TI-BASIC Nspire (on ARM processor) for TI-Nspire and TI-Nspire CAS TI rarely refers to the language by name, but the name TI-BASIC has been used in some developer documentation.
TI-83 seriesThe TI-83 series is a series of graphing calculators manufactured by Texas Instruments. The original TI-83 is itself an upgraded version of the TI-82. Released in 1996, it was one of the most popular graphing calculators for students. In addition to the functions present on normal scientific calculators, the TI-83 includes many features, including function graphing, polar/parametric/sequence graphing modes, statistics, trigonometric, and algebraic functions, along with many useful applications.
TI-Nspire seriesThe TI-Nspire is a graphing calculator line made by Texas Instruments, with the first version released in July 2007. The calculators feature a non-QWERTY keyboard and a different key-by-key layout than Texas Instruments's previous flagship calculators such as the TI-89 series. The original TI-Nspire was developed out of the TI PLT SHH1 prototype calculator (which itself was derived from the Casio ClassPad 300), the TI-92 series of calculators released in 1995, and the TI-89 series of calculators released in 1998.
TI-92 seriesThe TI-92 series of graphing calculators are a line of calculators produced by Texas Instruments. They include: the TI-92 (1995), the TI-92 II (1996), the TI-92 Plus (1998, 1999) and the Voyage 200 (2002). The design of these relatively large calculators includes a QWERTY keyboard. Because of this keyboard, it was given the status of a "computer" rather than "calculator" by American testing facilities and cannot be used on tests such as the SAT or AP Exams while the similar TI-89 can be.
