Also see efg's Mathematics Projects Page and Mathematics Reference Library.
Constants mathrelated constants (pi, e, logarithm constants, ...), computerrelated constants (MinDouble, MaxDouble. ...) 

f(x) = cos(2x + 3)  General Math Functions arithmetic functions (ceil, floor, hypot, muldiv, poly, round, trunc, ...), logarithm/exponential functions (ln, log, log2, exp, power, ...), trigonometric functions (sin, cos, tan, arcsin, arccos, arctan, atan2, ...) conversions and formatting (FloatToStr, IntToStr, Format, Trim, ...), financial functions (NetPresentValue, Payment, SLNDepreciation, ...), sorting, discrete math (quicksort, insertion sort, equivalence classes, ...), miscellaneous (IsNaN, Get/Set87ControlWord, GetRoundMode, ...) 
Engineering Mathematics hyperbolic functions (sinh, cosh, tanh, inverse functions, ...), special functions (bessel functions, beta, gamma, erf, ...), complex math and functions, linear algebra, matrices, eigenvalues, eigenvectors, digital signal processing, fourier transforms, FFTs ordinary and partial differential equations 

Numerical Methods interpolation, extrapolation, numerical integration/derivatives, polynomials, functional evaluation, Chebyshev approximation, optimization (simplex, powell, ...), root finding, nonlinear equations 

Statistics and Probability statistics (min, max, sum, mean, stddev, skew, kurtosis, ...), probability (binomial, pnorm, randg, factorial, Stirling, ...) curve fitting, regression, least squares, data modeling 

Secret Message  Cryptography and MultiplePrecision Arithmetic 
((A + B) * (C + D))  Parsers and Mathematical Expression Evaluators 
Notes:  1.  Definitions for all Delphi Math unit functions are listed for
quick reference. 
2.  Many of the functions listed here are Pascal functions, which should be easily translated to Delphi. 

3.  Additional links can be found on many of the pages. 
Links Verified 14 Jul 2000
Updated 18 Feb 2002
since 1 Nov 1998