Re: [Help]How to reprensent the result in vector form?

*To*: mathgroup at smc.vnet.net*Subject*: [mg51584] Re: [Help]How to reprensent the result in vector form?*From*: "Steve Luttrell" <steve_usenet at _removemefirst_luttrell.org.uk>*Date*: Sat, 23 Oct 2004 00:22:49 -0400 (EDT)*References*: <cl9t1d$7m0$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

You can use a replacement rule to convert your expression into the compact form that you want: Define the replacement rule. crossrule = {a3_ b2_ -a2_ b3_,a1_ b3_ -a3_ b1_,a2_ b1_ -a1_ b2_} -> myCross[{b1,b2,b3},{a1,a2,a3}]; Apply the rule to your expression. result = {-u3 v2 + u2 v3, u3 v1 - u1 v3, -u2 v1 + u1 v2}/.crossrule which gives the output myCross[{u1,u2,u3},{v1,v2,v3}] You could make the notation more compact by doing this result /. {{u1,u2,u3} -> u,{v1,v2,v3} -> v} which gives the output myCross[u,v] Another (related but more sophisticated) method is to use the Utilities`Notation` package to implement the reformatting of your output automatically. This includes a way of defining infix operators so that you can get an output that looks like u x v rather than myCross[u,v] Steve Luttrell "melon" <sweetmelon at gmail.com> wrote in message news:cl9t1d$7m0$1 at smc.vnet.net... >I used mathmetica5 to solve a vector equation. Mathmetica expands the > result into sub-variable form. But I want to get the vector form. How > to do that? > > ex: > Solution: > {-u3 v2 + u2 v3, u3 v1 - u1 v3, -u2 v1 + u1 v2} > I want mathematica give me {u cross v} > > p,s, Could you add me into the forum? Thank you very much. Regards. > > ShenLei >

**Follow-Ups**:**Re: Re: [Help]How to reprensent the result in vector form?***From:*DrBob <drbob@bigfoot.com>