Hello,
I do not have much experience with maxima and still ?find plenty of
things, which I do not understand:
When including the function in line %i39 in an ev() and defining r:a
thus log(r/a)=log(a/a)=0, apparently also 4*c4*r is set zero...
A work around (storing %i39 in s) and evaluating ev(s,r:a) yields the
expected result (%o42).
I am confused...
(%i37) kill(r,w,a,c1,c2,c3,c4);
(%o37) done
(%i38) w: c1+c2*r^2+c3*log(r/a)+c4*r^2*log(r/a)+w1;
4
p r 2 r r 2
(%o38) ---- + c4 r log(-) + c3 log(-) + c2 r + c1
64 K a a
(%i39) s: ratexpand(diff(diff(w,r)*r,r));
3
p r r
(%o39) ---- + 4 c4 r log(-) + 4 c4 r + 4 c2 r
4 K a
(%i40) ev(ratexpand(diff(diff(w,r)*r,r)),r:a);
3
a p
(%o40) ---- + 4 a c2
4 K
(%i41)
(%i42) ev(s,r:a);
3
a p
(%o42) ---- + 4 a c4 + 4 a c2
4 K
thank you in advance for help
al