Algebraic Differentiation Engine

 Math::Calculus::Differentiate can take an algebraic expression,
 parse it into a tree structure, modify the tree to give a representation
 of the differentiated function, simplify the tree and turn the tree back
 into an output of the same form as the input.
 .
 It supports differentiation of expressions including the +, -, *, / and ^
 (raise to power) operators, bracketed expressions to enable correct precedence
 and the functions ln, exp, sin, cos, tan, sec, cosec, cot, sinh, cosh, tanh,
 sech, cosech, coth, asin, acos, atan, asinh, acosh and atanh.