Question

please answer this question and take points and also brain list mark.. pls give me the correct answer then I will select

Answer 1

Answer:

Step-by-step explanation:

As, the number of surjections from A to B is equal to the number of functions from A to B minus the number of functions from A to B whose images are proper subsets of B.

⇒  And, the number of functions from a set with n number of elements into a set with m number of elements =m  

n

.

So, the number of surjections from A into B where,

⇒  A={1,2,....,n} and B={a,b} is 2  

n

−2 (As, two functions can be many-one into functions )