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Author Comment/Response
Bill Simpson
11/14/12 6:17pm

Simplify does not understand it can factor an expression independent of the variable of integration outside the integral.

A user replacement rule can make this happen.

In[1]:= Simplify[Integrate[f[x,z]Sin[θ],{z,0,1}] /.Integrate[q_*r_,{v_,l_,h_}] /;FreeQ[r,v] :> r*Integrate[q,{v,l,h}]-Sin[θ]Integrate[f[x,z],{z,0,1}]]

Out[1]= 0

Test this very carefully. Think about zeros and infinities and all the other special cases that can happen. User replacement rules are difficult to get right and can easily result in errors. It is also possible that //. or ReplaceRepeated might be needed in place of /. or Replace if you happen to have more than one factor in the integrand that is independent of the variable of integration.

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Subject (listing for 'Reduced question of last one')
Author Date Posted
Reduced question of last one Xizheng 11/10/12 05:51am
Re: Reduced question of last one Chenyu Lue 11/14/12 03:56am
Re: Reduced question of last one Bill Simpson 11/14/12 6:17pm
Re: Reduced question of last one Nasser M. Ab... 11/14/12 8:27pm
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