>>436
左は
x^5＋y^5＝xx･x^3＋yy･y^3≦(xx+yy)･(xx+yy)^(3/2)＝(xx+yy)^(5/2),
x^10＋(xy)^5＋y^10≦(x^5＋y^5)^2≦(xx+yy)^5,