Show that the function f : R → R : f(x) = x4 is many - one and into.
To show: f: R → R : f(x) = x4 is many - one into.
Proof:
f(x) = x4
⇒y = x4
Since the lines cut the curve in 2 equal valued points of y, therefore, the function f(x) is many ones.
The range of f(x) = [0,∞)≠R(Codomain)
∴f(x) is not onto
⇒f(x) is into
Hence, showed that f: R → R : f(x) = x4 is many - one into.