why does maxima not do this obvious simplification?




On Sun, 24 Jan 2010, Thomas Plehn wrote:

< %i*sqrt(sqrt(b^2+a^2)-a)*sqrt(sqrt(b^2+a^2)+a)+a
< 
< !
< =  a + b*%i
 
It does, just not automatically,

(%i2) %i*rootscontract(sqrt(sqrt(b^2+a^2)-a)*sqrt(sqrt(b^2+a^2)+a))+a;

(%o2) %i*sqrt(b^2)+a
(%i3) declare(b,real); assume(b>0);

(%o3) done
(%o4) [b > 0]
(%i5) %o2;

(%o5) %i*sqrt(b^2)+a
(%i6) ev(%,nouns);

(%o6) %i*b+a

Leo

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.