Re: General--Exponential simplifications by default

*To*: mathgroup at smc.vnet.net*Subject*: [mg69008] Re: [mg68966] General--Exponential simplifications by default*From*: Daniel Lichtblau <danl at wolfram.com>*Date*: Sat, 26 Aug 2006 02:04:56 -0400 (EDT)*References*: <200608250935.FAA09304@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

guillaume_evin at yahoo.fr wrote: > Hi ! > > I want to avoid simplifications when Mathematica integrates expressions with exponential terms. For example, I have : > > In[8]= Espcond[y_] = Integrate[x*Densx[x, y], {x, 0, Infinity}, Assumptions -> alpha > 0] > Out[8]= E^(-2eta y)(-theta + E^(eta y)(2+theta))/(2alpha) > > I do not want to have a factorization by E^(-2eta y). More precisely I would like to have the following result: > Out[8]= (-theta E^(-2eta y)+ E^(-eta y)(2+theta))/(2alpha) > > I guess there is a way to tackle this problem with "ComplexityFunction" and "Simplify", but I tried different things such as "ComplexityFunction -> (Count[{#1}, Exp_, ∞] &)" in the "Simplify" function but no change appears. > > Is someone could give me some tricks on how tu use the "ComplexityFunction" ? > > Thank you in advance. > > Guillaume > > Link to the forum page for this post: > http://www.mathematica-users.org/webMathematica/wiki/wiki.jsp?pageName=Special:Forum_ViewTopic&pid=12974#p12974 > Posted through http://www.mathematica-users.org [[postId=12974]] Could Collect with respect to powers of the exponential. In[59]:= ee = E^(-2eta*y)*(-theta + E^(eta*y)(2+theta))/(2*alpha); In[60]:= InputForm[Collect[ee, Exp[eta*y]]] Out[60]//InputForm= -theta/(2*alpha*E^(2*eta*y)) + (2 + theta)/(2*alpha*E^(eta*y)) Daniel Lichtblau Wolfram Research

**References**:**General--Exponential simplifications by default***From:*guillaume_evin@yahoo.fr