Re: Using Coefficient on an equation

*To*: mathgroup at smc.vnet.net*Subject*: [mg95444] Re: [mg95433] Using Coefficient on an equation*From*: "Scot T. Martin" <smartin at deas.harvard.edu>*Date*: Mon, 19 Jan 2009 02:54:56 -0500 (EST)*References*: <200901181033.FAA13999@smc.vnet.net>

Carlos, here may be what you're looking for: In[1]:= f=a*x^2+b*x+c==0 Out[1]= c+b x+a x^2==0 In[2]:= Coefficient[f,x^2] Out[2]= 0 In[3]:= Coefficient[f[[1]],x^2] Out[3]= a On Sun, 18 Jan 2009, carlos at colorado.edu wrote: > If f=a*x^2+b*x+c, Coefficient[f,x^2] obviously returns a. > But if f=a*x^2+b*x+c==0, it returns 0. > > The problem arose using the Calculus`VariationalMethods` package. > It (unfortunately) returns the Euler-Lagrange equations as > such, so I have to remove the useless ==0 appendage for > Coefficient to work properly. Is there a simple direct way out? > >

**References**:**Using Coefficient on an equation***From:*carlos@colorado.edu