Re: Taking LCM in a polynomial expression

*To*: mathgroup at smc.vnet.net*Subject*: [mg95402] Re: Taking LCM in a polynomial expression*From*: m.r at inbox.ru*Date*: Sat, 17 Jan 2009 05:32:22 -0500 (EST)*References*: <gkn5pa$iob$1@smc.vnet.net>

Srikanth wrote: > Hi > I have a symbolic matrix that I invert. When I take each individual > entry of the resulting matrix, I get an expression of the form: > num1/den1 + num2/den1 + .... + num_n/den1 > where den1 is the determinant of the matrix. I'd like to get an > expression of the form: > Num/Den. > > I tried using Simplify (as well as multiplying the matrix by its > determinant), but it doesn't seem to help. Any suggestions? > > On a related note, the final Num is a polynomial in two variables - > say x,y. I'd like to arrange it in decreasing powers of x - like f1(y) > x^n + f2(y) x^n-1... + constant. What function should use? Is there > any way to both in a single step? > > Thanks a lot > Srikanth As mentioned in tutorial/PolynomialOrderings, in version 7 it's possible to control the sorting of polynomial terms/factors to some extent in TraditionalForm output: In[1]:= x y^2 + x^2 y + 1 // TraditionalForm[#, ParameterVariables :> {y}]& Out[1]//TraditionalForm= y x^2+y^2 x+1 Maxim Rytin m.r at inbox.ru