MathDB
Turkish NMO First Round - 2000 P-32 (Algebra)

Source:

July 8, 2012

Problem Statement

Find the sum of all possible values of f(2)f(2) such that f(x)f(y)f(xy)=yx+xyf(x)f(y)-f(xy) = \frac{y}{x}+\frac{x}{y}, for every positive real numbers x,yx,y
<spanclass=latexbold>(A)</span> 52<spanclass=latexbold>(B)</span> 54<spanclass=latexbold>(C)</span> 54<spanclass=latexbold>(D)</span> 32<spanclass=latexbold>(E)</span> None <span class='latex-bold'>(A)</span>\ \frac{5}{2} \qquad<span class='latex-bold'>(B)</span>\ -\frac{5}{4} \qquad<span class='latex-bold'>(C)</span>\ \frac{5}{4} \qquad<span class='latex-bold'>(D)</span>\ \frac{3}{2} \qquad<span class='latex-bold'>(E)</span>\ \text{None}