YLL討論網

設，求證:

x^(1/3)+y^(1/3)+z^(1/3)=0
x^(1/3)+y^(1/3)=-z^(1/3)，兩邊立方
x+y+3x^(1/3)*y^(1/3)*[x^(1/3)+y^(1/3)]=-z
x+y+3x^(1/3)*y^(1/3)*[-z^(1/3)]=-z
x+y+z=3x^(1/3)*y^(1/3)*z^(1/3)
(x+y+z)^3=27xyz   Q.E.D