Re: Re: Simplifying Problems
- To: mathgroup at smc.vnet.net
- Subject: [mg22497] Re: [mg22409] Re: Simplifying Problems
- From: Jacqueline Zizi <jazi at club-internet.fr>
- Date: Sun, 5 Mar 2000 00:24:33 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
If you put and evalutate in 3 different cells: f [0] = \[Pi]; f [k_; k \[Element] Integers] := 0 f [k_] := Sin [k \[Pi]] /k Then you can check that, for example, : f [3/4 ], f [2/3 ], f [2 ], f [0] return what you wants. Then your wanted sum will evaluate well. For example: f [3/4 ] + f [2/3 ] + f [2 ] + f [0] + f[3/2] will give -2/3+ 2 Sqrt [2]/3+ 3 Sqrt [3]/4 + Pi Just be carefull that in reality, Sin[0]/0 is not defined, nor is 2/0. You are free to put what you want, for example Pi for 0. QUESTION ========= Hi, > ------------------------ > First question: > ------------------------ > I have an expression which has a sum of a number of sinc-like terms. For > example, > > f[k] = Sin[k Pi] / k > > If I try using simplify with the assumption that k is an integer I get > > In[2]:= > Simplify[f[k], k \[Element] Integers] > > Out[2]= > 0 > > Although this is true for most integers, it is incorrect for the integer > k==0 since f[0] = Pi. So why is this happening? I would have expected it > to either leave the expression untouched or to give me an If expression. etc..........................................................................................