MathGroup Archive 1998

[Date Index] [Thread Index] [Author Index]

Search the Archive

How does a rule get applied?



Hi,

I'm having trouble understanding how rules are applied after /. Consider
the following example:
          x^a + x^(1+a)  /. x^(n_) + x^(n_+1) ->0
          x^3 + x^(1+3)  /. x^(n_) + x^(n_+1) ->0
          x^3            /. x^(n_) ->0

Out[388]= 
                0

Out[389]=
                 3    4
                x  + x

Out[390]=
                0


Could anyone please explain to me why 

        x^a + x^(1+a)  /. x^(n_) + x^(n_+1) ->0 

returns 0 (as expected), whereas

        x^3 + x^(1+3)  /. x^(n_) + x^(n_+1) ->0

returns

                 3    4
                x  + x 

instead of 0?

Thanks for your help.   



  • Prev by Date: how to replace...?
  • Next by Date: Re: Matrix manipulation
  • Prev by thread: RE: Re: how to replace...?
  • Next by thread: Re: How does a rule get applied?