|WikiProject Mathematics||(Rated C-class, High-priority)|
elementary Leibniz differentials
I look in vain in wikipedia for an elementary explanation of the differential, (not the derivative). The Leibniz notations, and assumes dx and dy. Formal differentiation can be defined: if x is a variable then so is dx, if x is constant then dx = 0, if x is an independent variable then dx is constant and d2x = 0, the sum rule d(x+y) = dx+dy, and the product rule d(x·y) = dx·y+x·dy. This is sufficient to deduce differentiation of formal power series. Differentiation of an algebraic equation (such as x2+y2 = r2) gives a differential equation (such as x·dx + y·dy = 0). Perhaps this is what this technical article on differential algebra is about ? Bo Jacoby 08:06, 7 August 2007 (UTC).
Graded derivation redirects here, but it is not mentioned in the article; on the other hand there is a section Derivation (abstract algebra)#Graded derivations! Anyone want to sort this out? PJTraill (talk) 00:00, 4 February 2014 (UTC)