evaluation and substitution



Hello

I don't understand why Maxima has two behavior upon the same problem.
First :
f(x)=log(x)+x;
ev(f(x),log(x)=1);
returns log(x)+x
Second 
f : f(x);
ev(f,log(x)=1);
returns 1+x qui is correct.

Why Maxima doen't do the substitution in the first case ?
-- 
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Michel Gosse 
michel.gosse@ac-poitiers.fr
michel.gosse@freesbee.fr
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