The given inequality is equivalent to:
[x^2 + y^2 - x^2y - xy^2 \geq 0]
[x^2(1-y) - y^2x \geq 0]
[x^2(1-y) \geq y^2x]
Dividing both sides by $x$ (assuming $x \neq 0$), we get:
[x(1-y) \geq y^2]
[x - xy \geq y^2]
[x \geq y^2 + xy]
[x \geq y(x+y)]
Now, the fact that $x^2 + y^2 \geq x^2y + xy^2$ is the same as the fact that $x \geq y(x+y)$ for $x,y \in \mathbb{R}$.
The given inequality is equivalent to:
[x^2 + y^2 - x^2y - xy^2 \geq 0]
[x^2(1-y) - y^2x \geq 0]
[x^2(1-y) \geq y^2x]
Dividing both sides by $x$ (assuming $x \neq 0$), we get:
[x(1-y) \geq y^2]
[x - xy \geq y^2]
[x \geq y^2 + xy]
[x \geq y(x+y)]
Now, the fact that $x^2 + y^2 \geq x^2y + xy^2$ is the same as the fact that $x \geq y(x+y)$ for $x,y \in \mathbb{R}$.