Almost everything about Activation Functions ! 

Buddy sry to say Sigmoid is bit wrong It's sets the o/p between 0 and 1 Not -1 and 1

Nice video! But I think u have drawn tanh curve in place of sigmoid graph

In your machine learning playlist.. most of the videos are twice. Update it please.

When to use activation functions and in which circumstances like in your image classifier for dog n cat, You have used both relu and sigmoid. How you got to know that you have use these activation functions ?

please you have to answer to my question ??!!