Suppose f1 and f2 are non – zero one – one functions from R to R. Is necessarily one – one? Justify your answer. Here,
is given by
for all x ∈ R.
TIP: – One – One Function: – A function is said to be a one – one functions or an injection if different elements of A have different images in B.
So, is One – One function
⇔ a≠b
⇒ f(a)≠f(b) for all
⇔ f(a) = f(b)
a = b for all
Let, f1: R → R and f2: R → R are two non – zero functions given by
f1(x) = x3
f1(x) = x
From above function it is clear that both are One – One functions
Now, given by
⇒
⇒
Again,
defined by
f(x) = x2
Now,
⇒ f(1) = 1 = f( – 1)
Therefore,
f is not One – One
⇒ is not One – One function.
Hence it is not necessarily to be one – one function.