Beer soaked ideas follow.
With capital X and Y, still not the same size
[MATH]\sqrt[3]{XY^2} = \sqrt[3]{X}\sqrt[3]{Y^2} = X^{1/3}Y^{2/3}[/MATH]But with [MATH]X^1[/MATH][MATH]\sqrt[3]{XY^2} = \sqrt[3]{X^1}\sqrt[3]{Y^2} = X^{1/3}Y^{2/3}[/MATH]No cigar with
[MATH]\sqrt[3]{xy^2} = \sqrt[3]{x^1}\sqrt[3]{y^2} = x^{1/3}y^{2/3}[/MATH]Enclosing x in parentheses, it looks as if they are almost the same size (in the 2nd case).
Maybe it's just me beer goggles.
[MATH]\sqrt[3]{xy^2} = \sqrt[3]{\big(x\big)^1}\sqrt[3]{y^2} = x^{1/3}y^{2/3}[/MATH][MATH]\sqrt[3]{xy^2} = \sqrt[3]{(x)^1}\sqrt[3]{y^2} = x^{1/3}y^{2/3}[/MATH][MATH]\sqrt[3]{xy^2} = \sqrt[3]{\big(x\big)}\sqrt[3]{y^2} = x^{1/3}y^{2/3}[/MATH]