@Markiyan Hirnyk 

Well! a greate clue! Now I shall think and search for the algorithms behind continuity checking of a function that might be incorporated in Maple! Thanks.

@Alejandro Jakubi 

A nice work my friend. I have learnt this new thing from you how to trace codes of Maple. This way, I am very curious to know what does the developer mean by that false?

@Preben Alsholm 

That's right and thanks for your nice response. I have argued about the incorrectness of the the 0 in this way that I am multiplying increasing numbers starting from 1/2 to 1. By the way, I wonder why this happened in Maple! In fact I am seeking the reason why such a thing happened and are there any similar situations and how to identify and take care of such situations?