Share your great codes and achievements you achieved in your coding life.(Amazing challenge also available!)

Question

Welcome Sololearners !!!
Please share your amazing codes that you have created by own that got a good number of likes on it.You can also share the stories related to your codes like,why you decided to make it,what you have learnt from that,etc.
I also want to give a challenge to you all:-
Challenge aim:-
1.Create a code that can do differentiation with algebraic terms such as 4x²,2x³,etc.
2.All languages are Welcome !!!
Challenge Time:-
7 days
Winner Announcement:-
On December,1,2017
Try this now !!!

Answer 1

https://code.sololearn.com/WvDOIdE8L0eF/?ref=app

Answer 2

Anyone trying....?