Re: Re: vectors

*Subject*: [mg3219] Re: [mg3174] Re: vectors*From*: penny at edu-suu-scf.sc.suu.edu (Des Penny)*Date*: 17 Feb 1996 21:21:19 -0600*Approved*: usenet@wri.com*Distribution*: local*Newsgroups*: wri.mathgroup*Organization*: Wolfram Research, Inc.*Sender*: daemon at wri.com

>Can anyone give me some direction regarding the graphing of lines >and planes in 3D using vector equations? I'd like to convert the >vector equation of a plane in scalar product form, ie r.n = p, to >its graphic representation, for example. > >Paul Marshall Hi Paul: Lets say you want to find and plot the plane passing through the point whose position vector is r0. The plane must be perpendicular to n. In: n={1,2,3} r0={4,1,5} r={x,y,z} The position vector r is a position vector of any point in the plane. Since the vector r-r0 must lie in the plane and therefore be perpendicular to n, we have the equation of the plane as: In: eq= (r-r0).n==0 This returns the equation of the plane and stores this equation in "eq". We now solve this equation for z in terms of x and y and plot the plane as follows: In: sol= Solve[eq,z]; Plot3D[z /. sol[[1]], {x,3,5},{y,0,2}]; Hope this helps, Cheers, Des Penny ========================== Des Penny Physical Science Dept. Southern Utah University Cedar City, UT 84720 VOICE: (Office): (801) 586-7708 (Home) : (801) 586-2286 FAX: (801) 865-8051 e-mail: penny at suu.edu ==========================