Free math expressions software for windows

Desktop Expression application represents a free calculator designed to solve arithmetic expressions.
The expression calculator evaluates a single line artihmetic expression such as
sqrt(cos(60)+sin(30)).
Expression Calculator has been developed for Win32 platforms and has been tested with Windows XP.

Mathparser is a .NET assembly which contains a math parser developed in C# and will evaluate a mathematical expression and returns a double value.

Its a fast equation parser/evaluator with parse-tree builder and user-friendly interface for parsing and calculation a run-time defined math expression.
The math expressions is represented as string in a function style
F(x1, x2,..., xn) =f(x1, x2,..., xn)
, where
F(x1, x2,..., xn) - declares number and names of the variables;
f(x1, x2,..., xn) - math expression may contain:
-variables x1, x2,..., xn and numbers,
-arithmetic operations + - * / ^,
-supporting a large set of math functions: sqrt, sin, exp, cos, tan, ln, abs, acos, asin, atan, cosh, log10, sinh, tanh,
-constants e= 2.71828182845904 and pi= 3.14159265358979, and
-user defined functions and constants.
For example:
F(x, y) = 3*x^2+y^2+e/4,
F(x1, x2, y) = (x1-sin(x2))/y,
F()=5+6+pi.
Algorithm, which is used here, has been developed and implemented by Easy Math Solution and has different binary (static link library, dynamic link library and COM) implementation and programming approach (procedural and object oriented). It allows using EquTranslator in C/C++, C#, Delphi, VB and other languages and systems that can understand dll and COM.