Differentiation ?

*To*: mathgroup at smc.vnet.net*Subject*: [mg14668] Differentiation ?*From*: "Yves Gauvreau" <gauy at videotron.ca>*Date*: Sat, 7 Nov 1998 02:10:25 -0500*Sender*: owner-wri-mathgroup at wolfram.com

Hi, I saw this equation in a book (Sum => greek SIGMA) Sum ei^2 = Sum (yi^2 - 2 mu yi + mu^2) That easy to implement but there's this one D[ Sum ei^2, mu] = 2 Sum yi - 2 n mu and this one to E'E = Y'Y - B'X'Y + B'X'XB D[E'E,B] = -2 X'Y + 2X'XB the ' mean Transpose[] How can I implement these type of Differenciation ? Is it possible to do that in Mathematica ? Thanks Yves

**Follow-Ups**:**Re: Differentiation ?***From:*Jurgen Tischer <jtischer@col2.telecom.com.co>