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_, &#8734;] &)" in the "Simplify" function but no change appears.
>
> Is someone could give me some tricks on how tu use the "ComplexityFunction" ?
>
>
> 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

```

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