Re: querries

*To*: mathgroup at smc.vnet.net*Subject*: [mg119574] Re: querries*From*: "Kevin J. McCann" <Kevin.McCann at umbc.edu>*Date*: Fri, 10 Jun 2011 06:40:15 -0400 (EDT)*References*: <isq4o1$63f$1@smc.vnet.net>

It is probably because powers, x^y are multivalued. You can use expr//PowerExpand to short circuit these concerns. Be aware, however that the following does not give an answer Sqrt[b^2]==b but Sqrt[b^2]==b//PowerExpand Gives True, which means that the concerns about plus/minus are forgotten. Kevin On 6/9/2011 5:45 AM, Savits, Thomas H wrote: > 1) Why does Mathematica not give the value 0 to the expression > (mu*lambda)^(b) - (mu^b)*(lambda^b)? It seems to treat the expression (mu*lambda) as a new variable. I used the greek letters from the palette in the actual expression. > > 2) Many times I cannot get Mathematica to simplify expressions involving the exponential functions, e.g., it won't combine the arguments of the Exp functions. Is there a way to force this? > > Thanks, > Tom Savits > Statistics Department > University of Pittsburgh