Hello Devim,
> Rdx=matrix([sh*sp*sr+ch*cr,cp*sr,ch*sp*sr-cr*sh],[cr*sh*sp-ch*sr,cp*cr,sh*sr+ch*cr*sp],[cp*sh,-sp,ch*cp])
>
> sh and sp are not defined.(I assume maxima will keep them symbols.)
Two quick comments ---
(1) You want to write "Rdx : matrix (...)" i.e. with a colon instead
of an equal sign.
Colon is the assignment operator.
(2) If sh, ch, etc are sin and cos terms, your matrix Rdx is orthonormal
and its inverse is its transpose.
I find trigsimp (Rdx . transpose (Rdx)); => identity matrix
after assigning sh : sin(h); ch : cos(h); etc and reevaluating Rdx.
hth
Robert Dodier