AntonAntonov 

The MathEvaluator .NET library allows you to evaluate and compile any mathematical expressions from a string dynamically. It supports a wide range of operations and allows for the use of custom variables,... More information

This C# library includes functions that are missing in .NET: cot, sec, csc, acot, asec, acsc, coth, sech, csch, acoth, asech, and acsch. Also, it includes standard functions: sin, cos, tan, asin, acos, atan,... More information