Tip 120.

Many users of Mathcad criticize this program as wrong answers are got very often when you solve some trigonometrical equations with help of symbol mathematics[1]. The example of such misfire is showed in fig. 120. What is the matter here?! And point is that the symbol mathematics can not solve correctly even the simplest trigonometrical equation such as sin(x)=0: here we get zero answer though this equation has countless numbers of roots. Our equations f(x) consists of two factors that you can see in the title in fig. 120. But the right root is defined only of the first f1(x).

[1] Here we have to criticize not Mathcad, but Maple symbol mathematics is the utility that is putted in Mathcad from Maple.