Symbol mathematics that is built-in in Mathcad has one defect – it runs to limits: it always tries to give all answers with absolute accuracy. Because of it an expression that is ready for working with help of tools of symbol mathematics, after carrying off the cursor (after order for execution the command of symbol mathematics) becomes red. But it is the indication of beginnings a mistake or additional specifying for user.
· if an operator of symbol transform has become red, then it does not mean yet that the transform is possible: it is necessary to lead the cursor to the ablush operator (but many users of Mathcad do not do it) and to read carefully the error message;
· when you solve the problem with help of symbol mathematics it is worth to turn down one of “the absolutes” (absolutely all answers with absolute accuracy): in point 2 in the fig. 95 the additional operator float has allowed to find all solutions in the form of decimal fraction but not with absolute accuracy (in the form of analytical expression).
 Calculus mathematics of Mathcad is more “inclined to compromise” – it gives one answer from many existent with limited accuracy.