Re: display of function

*To*: mathgroup at smc.vnet.net*Subject*: [mg58524] Re: [mg58506] display of function*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Tue, 5 Jul 2005 06:34:16 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

p = {p1,p2,p3}; y={y1, y2, y3}; Use the dot product p.y p1*y1 + p2*y2 + p3*y3 p = {.3,.4,.3}; y={10000, 20000, 30000}; p.y 20000. For your function to work, you would need to use Part rather than Subscript and define n (i.e., provide a numerical value for the index upper limit). u[y_]:=Sum[p[[i]]*y[[i]],{i,1,Length[y]}]; u[y] 20000. Bob Hanlon > > From: "Bosch, Darrell" <bosch at vt.edu> To: mathgroup at smc.vnet.net > Date: 2005/07/05 Tue AM 01:57:45 EDT > Subject: [mg58524] [mg58506] display of function > > > Dear Math Group: > > The first equation below shows a function for u(y) which is > the sum of the products of pi times yi. In the following steps, I > assign values of p and y. How can I get Mathematica to display the > numerical value of u for the given p and y values? When I insert the > u[y] command, I just get a repeat of the equation I have entered. > Thanks for your suggestions. This group is a great help. Darrell > > > > u[y_] := Sum[Subscript[p, i]*Subscript[y, i], > > {i, 1, n}] > > > > p = {.3,.4,.3} > > > > y={10000, 20000, 30000} > > >