Commutativity of Connectives :

In this you will be aware of the fact that some arithmetic operators that have a property which it doesn't matter that way around you give the operator input. So than now we call this property as commutativity. Here by using example, where adding two numbers, is  doesn't matter which one comes first, means as a+b = b+a  for all  a  and  b but in the same is true for multiplication there not true for subtraction and division. 

The ^ , ∨ and ↔ connectives that are operate on two sub sentences like as have the commutativity property. Here we can express this with three tautologies:

So than, if there it helps to do so, at any time we see P^ Q that we can rewrite it as Q^ P so similarly for the other two commutative connectives.