If $af(x)+bf(\frac{1}{x})=x-1$, x ≠ 0 and a ≠ b, then f(2) =
Answer & explanation
Correct answer: option 4
Given, $af(x)+bf(\frac{1}{x})=x-1, x ≠ 0, a ≠ b$ …(i)
$⇒af(\frac{1}{x})+bf(x)=\frac{1}{x}-1$ …(ii)
a . (i) − b . (ii)
$⇒ (a^2 − b^2) f(x) = a(x-1)-b(\frac{1}{x}-1)⇒(a^2 − b^2) f(2)=a+\frac{b}{2}=\frac{2a+b}{2}$
$⇒f(2)=\frac{2a+b}{2(a^2-b^2)}$