we know that derivative of x^2 =2x. now we can write x^2 as x+x+x....(x times) then if we take defferentiation we get 1+1+1+.....(x times) now adding we get x . then which is wrong mathod.

for equating the differentiated equations of a function then the functions must be equal

for two functions f(x) and g(x) to be equal then domain and range of two funtions must be equal

but the range for x^2 and x+x+x+x...(x times) are not equal....so the functions are not equal....

so the differentiated equations of the both must not be equated