Hypæthrum

Part of a building not covered by a roof, Pompeiian Hypæthrum. as the central portion of an ancient Roman house. Hypæthral temples are arranged by Vitruvius under the seventh order, IMG:content-0719.png:[merged small][ocr errors][merged small][merged small][ocr errors][merged small][merged small] these values, IMG:content-0720.jpg:[ocr errors] X--X is called the hyperbolic cosine of x (denoted by Ch. x) and is called the hyperbolic sine of x (indicated by Sh. x). The other trigonometric hyperbolic functions, Tangent (Th), Cotangent (Cth), Secant (Sch.), and Cosecant (Csch), are derived as corresponding simple functions from the sine and cosine. Anti-hyperbolic functions may be formed from these, as from the simple trigonometric functions.