Re: Manipulation of equations and inequalities in "high-school style"

*To*: mathgroup at smc.vnet.net*Subject*: [mg19574] Re: Manipulation of equations and inequalities in "high-school style"*From*: hanson.nospam at physics.auburn.edu (James D Hanson)*Date*: Wed, 1 Sep 1999 23:07:06 -0400*Organization*: Auburn University Physics*References*: <7q9hdf$o62@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <7q9hdf$o62 at smc.vnet.net>, silvano at iprolink.ch (Silvano D'Orazio) wrote: > Does anybody know a Mathematica (3 or 4) package which allows > manipulaton of equations and inequalities like high-school students > are supposed to do? > > For example > > 2x+a = x-b subtract a > 2x = x-b-a divide by 2, subtract x > x = -b-a > > or > > (2^x-1)^(1/2) = 5b log both sides > (1/2)(x-1)log2 = log5 + logb multiply by 2, divide by log2 > > > 2(log5 + logb) add 1 > x-1 = -------------- > log2 > > and so on. > > I think I saw such a notebook or package some years ago, but I am not > able to find it any more. > I think I am not the only teacher who would find this very useful. > Thanks for all hints. > > Silvano D'Orazio > > > > -----------== Posted via Newsfeeds.Com, Uncensored Usenet News ==---------- > http://www.newsfeeds.com The Largest Usenet Servers in the World! > ------== Over 73,000 Newsgroups - Including Dedicated Binaries Servers ==----- Three extra bits you need, == instead of = for equations; Map to do something to both sides of the equation; and functions (the things you actually do). In[1]:= ? Map "Map[f, expr] or f /@ expr applies f to each element on the first level in \ expr. Map[f, expr, levelspec] applies f to parts of expr specified by \ levelspec." In[2]:= eq1 = (2 x + a == x - b) Out[2]= a+2 x==-b+x In[3]:= eq2 = Map[#-a &,eq1] Out[3]= 2 x==-a-b+x In[4]:= eq3 = Map[#-x &,eq2] Out[4]= x==-a-b -- James D. Hanson ph. (334) 844-5044 Department of Physics fax (334) 844-4613 206 Allison Laboratory Auburn University, AL 36849-5311 hanson.nospam at physics.auburn.edu