Re: Adding Vectors -- Newbie help please

*To*: mathgroup at smc.vnet.net*Subject*: [mg52052] Re: Adding Vectors -- Newbie help please*From*: Paul Abbott <paul at physics.uwa.edu.au>*Date*: Tue, 9 Nov 2004 01:36:36 -0500 (EST)*Organization*: The University of Western Australia*References*: <cmfc9b$7k3$1@smc.vnet.net> <cmhut5$ppb$1@smc.vnet.net> <cmklrk$jm3$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <cmklrk$jm3$1 at smc.vnet.net>, motz art <music at heart.com> wrote: > Ok; but I was hoping that there is a simpler way than the > following method to add two ac voltage vectors (for example): > > (220V, 225 degrees) > (100V, 16 degrees) > > Clear[r, x, y, Theta, rect, polar] > > (* Input vectors here *) > v1 := {220, 225}; > v2 := {100, 16}; No need for := here. Also, include Degree: v1 = {220, 225 Degree}; v2 = {100, 16 Degree} > rect[r_,Theta_] := { r Cos[Theta Pi/180] , r Sin[Theta Pi/180]} > polar[x_, y_] := {Sqrt[x^2 + y^2], ArcTan[x, y]180/Pi} Modify these to PolarToRectangular[{r_,Theta_}] := {r Cos[Theta] , r Sin[Theta]} RectangularToPolar[{x_, y_}] := {Sqrt[x^2 + y^2], ArcTan[x, y]/Degree} Alternatively, PolarToRectangular[{r_,Theta_}] := r Exp[I Theta] RectangularToPolar[z_] := {Abs[z], Arg[z]/Degree} > r1:= rect[v1[[1]], v1[[2]] ] // N; > r2:= rect[v2[[1]], v2[[2]] ] // N; > rt := p1 + p2 > > polar[rt[[1]], rt[[2]]] // N The addition of vectors (phasors) now reads RectangularToPolar[PolarToRectangular[v1]+PolarToRectangular[v2] // N] which I find a little less cumbersome. > This just seems so cumbersome, especially when compared to a > scientific calculator. You could, of course, write a palette or program buttons to do this, just like a scientific calculator. Cheers, Paul > On Sat, 6 Nov 2004 07:36:05 +0000 (UTC), David Bailey > <dave at Remove_Thisdbailey.co.uk> wrote: > > >motz art wrote: > >> Mathematica v5: How can I input vectors in polar form and > >> rectangular form? > >> > >> Example: > >> > >> a:= (r1, theta1) + (r2, theta2) Polar form. > >> > >> b:= (re1 , j* im1) + (re2, j*im2) Rectangular form > >> > >> I know this should be pretty basic, but I haven't found examples > >> of this kind of input. > >> > >> I would guess it would be something like: > >> > >> Polar[magnitude, phase] > >> Rectangular[Real, Imaginary] > >> > >> but, apparently not. (This is for electronics engineering.) > >> > >> Thanks for any help. > >> > >> > >> > >> > >> > >You can easily write a function to convert from polar to coordinate form: > > > >FromPolar[r_, theta_] := {r Cos[theta], r Sin[theta]} > > > >Note that this assumes your angles are measured in radians. Once all > >your vectors are in coordinate form you can add/subtract then directly: > > > >{1,2}+(3,4} > > > >produces > > > >{4,6} > > > >Regards, > > > >David Bailey > -- Paul Abbott Phone: +61 8 6488 2734 School of Physics, M013 Fax: +61 8 6488 1014 The University of Western Australia (CRICOS Provider No 00126G) 35 Stirling Highway Crawley WA 6009 mailto:paul at physics.uwa.edu.au AUSTRALIA http://physics.uwa.edu.au/~paul