Sum simplifying

*To*: mathgroup at smc.vnet.net*Subject*: [mg89200] Sum simplifying*From*: Lari <lari.jarvenpaa at luukku.com>*Date*: Thu, 29 May 2008 07:03:31 -0400 (EDT)

Hey, I'd like to simplify a following type of sum: In[62]:= Sum[a[k]*I + b[k], {k, 1, n}] - I*Sum[a[k], {k, 1, n}] - Sum[b[k], {k, 1, n}] In[63]:= FullSimplify[%] The result should obviously be zero; however, Mathematica returns the same expression. If I put n an integer value it knows how to simplify. How do I make it understand that also with a symbolic upper limit? Hope someone can help! Thanks, Lari