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AP EAMCET · Maths · Functions

If a real valued function \(f\) is defined by \(f(x)=\) \(\frac{a x+\sqrt{a^2-x^2}}{b x}\), then \(f\) is

  1. A only one-one
  2. B only onto
  3. C both one-one and onto
  4. D neither one-one nor onto
Verified Solution

Answer & Solution

Correct Answer

(C) both one-one and onto

Step-by-step Solution

Detailed explanation

\(f(x)=\frac{a x+\sqrt{x^2-a^2}}{b x}\) Then \(f^{\prime}(x)=\frac{-a^2}{b x^2 \sqrt{x^2-a^2}}\) if \(b>0 \Rightarrow f^{\prime}(x) 0 \Rightarrow f(x)\) is increasing \(\Rightarrow f(x)\) is one-one. Now, let \(y=\frac{a x+\sqrt{a^2-x^2}}{b x}\)…