Re: Re: Adding Vectors -- Newbie help please

*To*: mathgroup at smc.vnet.net*Subject*: [mg52041] Re: [mg52023] Re: Adding Vectors -- Newbie help please*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Mon, 8 Nov 2004 03:13:24 -0500 (EST)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

Define a function to add polar forms rect[{r_, theta_}] := Module[{t=theta Degree},r{Cos[t],Sin[t]}]; polar[{x_,y_}] := {Sqrt[x^2+y^2],ArcTan[x,y]/Degree} addPolar[p__] := polar[Plus@@(rect/@{p})]; v1:={220,225}; v2:={100,16}; addPolar[v1,v2]//N {141.127,-114.908} v3={60,30}; addPolar[v1,v2,v3]//N {98.2845,-94.3623} Bob Hanlon > > From: motz art <music at heart.com> To: mathgroup at smc.vnet.net > Date: 2004/11/07 Sun AM 01:04:10 EST > To: mathgroup at smc.vnet.net > Subject: [mg52041] [mg52023] Re: Adding Vectors -- Newbie help please > > 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] > > 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} > > (* Input vectors here *) > v1 := {220, 225}; > v2 := {100, 16}; > > r1:= rect[v1[[1]], v1[[2]] ] // N; > r2:= rect[v2[[1]], v2[[2]] ] // N; > rt := p1 + p2 > > polar[rt[[1]], rt[[2]]] // N > > This just seems so cumbersome, especially when compared to a > scientific calculator. > > > > 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 > >