Complicated Rotation

*To*: mathgroup at smc.vnet.net*Subject*: [mg27237] Complicated Rotation*From*: Yas <yast at optushome.com.au>*Date*: Tue, 13 Feb 2001 03:35:44 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Dear mathgroup, I have a problem that I have been trying to do in mathematica. I have a number of functions defined as, f1[t_]:=c Sin[t] f2[t_]:=d Cos[t] f3[t_]:=Sqrt[f1^2 + f2^2] x[t_]:=ArcCos[f1/f2] y[t_]:=g Sec[x] where c, d and g are constants. In addition I have a 3x3 matrix with elements {{a11,a12,a13},{a21,a22,a23},{a31,a32,a33}} and each of the elements of the matrix can be defined as a function of t: ie. a11[t_]:=Sin[b]^2 Cos[y] + Cos[x]^2 etc, etc, where b can be constant. I want to multiply the matrix by a unit initial vector s0 = {1,0,0}. So I have defined the matrix as r[t_]. And the final vector sf[t_] = r.s0. So at t = 0, sf = s0. And at successive increments of time sf[1] = r[1]*s0 sf[2] = r[2]*sf[1] sf[3] = r[3]*sf[2] | | sf[n] = r[n]*sf[n-1] Unfortunately I am not much of a programmer and I have had various attempts with Map and Do and Table constructs with various errors. Could someone please explain a method whereby I could get a list of sf values so that I can plot sf versus time. Thanks in advance Yas

**Follow-Ups**:**Re: Complicated Rotation***From:*Matthias Hertel <wir95cgu@studserv.uni-leipzig.de>