Factor, Expand. Daytime Hours.

*To*: mathgroup at smc.vnet.net*Subject*: [mg32299] Factor, Expand. Daytime Hours.*From*: Matthias.Bode at oppenheim.de*Date*: Sat, 12 Jan 2002 05:18:08 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Dear Colleagues, once again I am doing maths with my son and in doing so we look for more solutions to the textbook problems after having solved them using our built-in biochemical processors. So: 1. Factor[a^2 - b^2] yields - predictably - (a - b)*(a + b). The question "what yields the factorization of a^2 + b^2" is not far-fetched. How can I coax MATHEMATICA into giving: (a - I*b)*(a + I*b)? Are there more "simple" solutions of the same structure (... - ...)*(... + ...) or some wizardry like (... + or - ...)^t, where t is some composite expression ? 2. Where can I find the function that gives the daytime hours between sunrise and sunset as a function of date and latitude? Thank you for your help. Best regards, Matthias Bode Sal. Oppenheim jr. & Cie. KGaA Koenigsberger Strasse 29 D-60487 Frankfurt am Main GERMANY Tel.: +49(0)69 71 34 53 80 Mobile: +49(0)172 6 74 95 77 Fax: +49(0)69 71 34 95 380 E-mail: matthias.bode at oppenheim.de Internet: http://www.oppenheim.de