false nonzero imaginary part after real substitution
Publié : dim. oct. 10, 2021 8:48 pm
Hi,
There's a strange thing happening when substituting in giac 1.7.0-25:
Since values for x1 and x2 are both real, the result should obviously be real also.
However, the command
gives
which is strange on its own because it contains the imaginary unit. Also
yields
which is a contradiction.
There's a strange thing happening when substituting in giac 1.7.0-25:
Code : Tout sélectionner
s:=subs(ln(1+x1^2)-x2,[x1=-sqrt((sqrt(2*(sqrt(17)-1))-2)/2),x2=(-sqrt(17)+1)/2])However, the command
Code : Tout sélectionner
im(s)Code : Tout sélectionner
(1-i)*pi/2Code : Tout sélectionner
im(normal(s))Code : Tout sélectionner
pi/2