Re: How to remove curly brackets and arrow symbols from a list.
- To: mathgroup at smc.vnet.net
- Subject: [mg58209] Re: How to remove curly brackets and arrow symbols from a list.
- From: David Bailey <dave at Remove_Thisdbailey.co.uk>
- Date: Thu, 23 Jun 2005 05:33:45 -0400 (EDT)
- References: <d9av83$10a$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
T. K. Ghosh wrote: > Hi Math Guru, > > I will be very happy if you could help me to solve the following problem. > The simplified version of my problem is the following. > I have a quadratic equation with a parameter, say "p". > > Define the function: > f[x_] := A*X^2 + B*X*p + D with A, B and D are given. > "p" is a parameter. > I solve this equation for a given p: > w = Solve[f[x]] == 0, X]. > Now I want to make a Table for the solutions of this > quadratic equation for different values of "p". > So I write, > Table[{p,sol},{p,0,10,1}. > I will get a table which will look like, > 0 {w -> a} {w -> -a} > 1 {w -> b} {w -> -b} > 2 {w -> c} {w -> -c} > and so on......... > > How can I remove the curly brackets and the arrow symbol > from the TableForm? I would like to plot the 1st column > vs. 2nd or 3rd column. I must remove those brackets. > and I wish to get the following form: > 0 a -a > 1 b -b > 2 c -c > > > Hope this can be done easily which I am not aware. > Any suggestion/solution to this problem is most welcome. > Thanking you in advance. > TKG. > Hello, First please note that 'x' and 'X' are distinct variables. If you give a quadratic equation to Solve, you will get back a list of TWO solutions - because that is the nature of quadratic equations! If you don't care which solution you want, you could just select one of these: w=Solve[f[x] == 0, x][[1]] At this point w will have a value something like {x->answer}. This is extremely useful in general because you can use it to substitute the value of x into any expression involving x. In your case you want: w= x/.Solve[f[x] == 0, x][[1]] Now w is the answer you want (as a function of p) and you can use it to build your table without any curly brackets! If I were you I would invest some time reading that heavy brick that came with your Mathematica disks - or even go on a course - once you learn a little more you will see how all this clicks together. David Bailey http://www.dbaileyconsultancy.co.uk