Trigonometry (from Greek
trigōnon "triangle" + metron "measure") is a branch of mathematics that deals with triangles, particularly those
plane triangles in which one angle has 90 degrees (right triangles). Trigonometry deals with relationships between
the sides and the angles of triangles and with the trigonometric functions, which describe those relationships.

Trigonometry has applications in both pure mathematics and in applied mathematics, where it is essential in many
branches of science and technology. It is usually taught in secondary schools either as a separate course or as
part of a precalculus course. Trigonometry is informally called "trig".
- Wikipedia

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while typing up your telephone line, and a nice lady's voice announced "You've Got
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