Theory of partial differentiation

Question

WHY A TOTAL DIFFERENTIATION CAN BE RECIPROCAL BUT PARTIAL DIFFERENTIATION CANNOT BE RECIPROCALed?

EX

if (dx/dy)=sinp then (dy/dx)=cosecp

BUT in case of partial differentiation reciprocal answer not always match.

WHY IS IT?

Answer 1

because in a partial derivative, the 'y' in your case is typically a function of several varibles (f(x,y,z,....)).