What is the physical meaning ofd(x?^{2}y^{2})

For example,

d(x^{2}) = 2x dx

This can be derived as,

d(x^{2})/dx = 2x

d(x^{2}) = 2x dx

Heredxcan be thought ofDelta x, rather than thinkingd/dxas an operation. So, small change inxis the^{2}product of "two times current value of x" and small change inWhat will be the similar deduction methodology forx.

d(xThanks a lot.^{2}y^{2}) = 2xy^{2}dx + 2yx^{2}dy?