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TS EAMCET · Maths · Functions

The number of bijective functions \(f: \mathbf{Z} \rightarrow \mathbf{Z}\) such that \(f(x+y)=f(x)+f(y) \forall x, y \in \mathbf{Z}\), is

  1. A two
  2. B four
  3. C zero
  4. D infinitely many
Verified Solution

Answer & Solution

Correct Answer

(A) two

Step-by-step Solution

Detailed explanation

Let \(x\) and \(y\) be any two elements in the domain \((Z)\), such that \(f(x+y)=f(x)+f(y)\) \(\ldots\) (i) Differentiating above expression w.r.t ' \(y\) ', keeping \(x\) constant, we get \(f^{\prime}(x+y)=f^{\prime}(y)\) Let \(y=0 \Rightarrow f^{\prime}(x+0)=f^{\prime}(0)\)…