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Relations And Functions

Question
CBSEENMA12032270

Prove that the function f : R → R , given by f (x) = 2x, is one-one and onto.

Solution

f : R → R is given by f (x) = 2x
Let x1, x2 ∈ R such that f (x1) = f (x2)
∴ 2x1 = 2 x2 ⇒ x1 = x2 ∴ f is one-one.
Also, given any real number y ∈ R, there exists
1 half space element of space R 
such that 
straight f open parentheses straight y over 2 close parentheses equals 2 comma space straight y over 2 equals straight y
∴ f is onto.