[neutralino]

Ok, let's take a look at what you want to do. You have said that you want to differentiate the function f(x)=x^2=x+x+x+...+x (with x terms), and you say that the answer is f'(x)=1+1+1+...+1 (with x terms). But this answer contains an x (namely in the part "x terms") which you haven't differentiated with respect to! This, there arises a second term x+x+x+...+x (with 1 term). Summing the two gives 2x, which is the answer.

secondly i wanted to know whats wrong in the second approach rather than suggest an alternative approach..

I've just told you what is wrong above!![/size]