Hey tell me the mistake... I have proved 2=1 x2= x*x=x+x+x+x+...(x times)lets take derivatives both side...d/dx(x2)=d/dx(x+x+x+x+...(xtimes))2x=1+1+1+1+...(x times)2x=x2=1 I can’t find the mistake...this is not possible..

It is pretty clear that, adding a number `x` times makes sense only if `x` is a positive integer. Hence the function X^2 is written this way. So the function X^2 exizts only for integers. This is against the basic requirement of differentiation. A function is differentiable only if it is continuous. But our function is defined only for integers. So it is not continuous. Its discrete and hence not differentiable. Hence wrong.