FUNCTIONS
Definition : A function (or mapping) f from set A to set B ( f : A → B ) is a relation which associates for each element x in A , a unique (exactly one) element y in B. Then the element y is expressed as y = f (x). y is the image of x under f . f is called map or transformation . If such a function exist , then A is called the domain of f and B is called co-domain of f . Types of Function : 1. One-One or One to One or Injective Function : A function f : A → B is said to be one-one if different element in A have different image in B . The condition is aslo expressed as f(a) = f(b) ⇒ a = b [As a ≠ b ⇒f(a) ≠ f(b)] 2. Onto or Surjective Function : A function f : A → B is said to be onto if every elemen...