Maxima: trigsimp() introducing errors ??


I have an expression q consisting of trigonometric terms, and q(delta3=0) = 
-k/2.

When I apply trigsimp(q), the resulting expression has a singularity at 
delta3 = 0 (see below). It appears that trigsimp() is introducing errors ??

Any assistance would be appreciated.

Regards,

C. Frangos.


(%i82) q;

(%o82) -k*Lc/(Lc*(cos(delta3)*sqrt(sin(delta3)^2*Lc^2
                                    /(2*sin(delta3)*L2+cos(delta3)*Lc)^2
                                    +1)
                 +1)
             +2*sin(delta3)*L2
               *sqrt(sin(delta3)^2*Lc^2/(2*sin(delta3)*L2+cos(delta3)*Lc)^2
                      +1))
(%i83) subst(0,delta3,q);

(%o83) -k/2
(%i84) subst(0,delta3,trigsimp(q));

Division by 0
 -- an error.  Quitting.  To debug this try debugmode(true);
(%i85)