Question

不等式证明题,X^3-y^3>x^2y-xy^2求证忘记说了x>y

Answer 1

X^3-y^3-(x^2y-xy^2)

=(x^3-x^2y)+(xy^2-y^3)

=x^2(x-y)+y^2(x-y)

=(x-y)(x^2+y^2)

所以,x>y时,X^3-y^3>x^2y-xy^2

x