MathDB
solve the system of equations

Source: China second round 2006 p3

March 10, 2012
algebrasystem of equationsalgebra unsolved

Problem Statement

Solve the system of equations in real numbers: {xy+zw=2x2y2+z2w2=6x3y3+z3w3=20x4y4+z4w4=66 \begin{cases} x-y+z-w=2 \\ x^2-y^2+z^2-w^2=6 \\ x^3-y^3+z^3-w^3=20 \\ x^4-y^4+z^4-w^4=66 \end{cases}