MathDB
maybe easy but good problem

Source: silk road

March 9, 2016
algebra

Problem Statement

Prove that there is no positive real numbers a,b,c,da,b,c,d such that both of the following equations hold.ab+bc+cd+da=6,ba+cb+dc+ad=32\frac{a}{b}+\frac{b}{c}+\frac{c}{d}+\frac{d}{a}=6 , \frac{b}{a}+\frac{c}{b}+\frac{d}{c}+\frac{a}{d}=32.