what is Onto function with example ?
A function f:X→Y is said to be an onto or surjective function if rng f =f( X)=Y i.e if every element of Y is the image of some element of X. e.g f:Z→Z, y=f(x)=x+2 is an onto function Because for every y belongs to Z set, x belongs to Z set also so the given function is an onto function.