1.at parse(sprintf("%.3f",subs(x=1, pdf))); it error said number expected for floating point format

i need to copy the whole formula to pdf := something then it can calculate

2. also it can not plot

%%%% copyright by Martin Lee 2011%%%%%%%

l := [12, 14, 27, 35, 46, 49];
sl := gfun[listtoseries](l, x, egf);
g := convert(sl, ratpoly);
g := g - subs(x=0, g);
g := g/subs(x=1, g);
parse(sprintf("%.3f",subs(x=1, g)));
parse(sprintf("%.3f",subs(x=0.9, g)));

How to reserve dx when diff a formula

when i diff x^2 , need to be 2*x*dx but it only 2*x

How to reserve dx?

How to get the polynomial successfully why return error expect a series valuation 1, what do it mean?

l := [12,14,27,35,46,49];
sl := listtoseries(l,x,revogf);
convert(sl,ratpoly);

with(gfun):
gfun['maxdegcoeff'] := 50:
gfun['maxdegeqn'] := 2:

i use number of balls in each basket to get a list, but all functions return fail? where is wrong? and how to use correctly?
l := [0,0,0,2,0,0,0,0,1,1,0,1,0,1,1,0,0,0,0,0,0,1,0,0,1,0,1,1,0,1,1,0,1,0,2,0,0,0,1,0,0,0,0,0,1,1,0,1,1]:
listtoratpoly([1,1,2,3,5,8,13],z);
listtoalgeq(l,y(x));

l := [12,14,27,35,46,49,31];
listtohypergeom(l,z);
guessgf(l,z);

i want to integrate dbeta at the bottom of the following code, however, it said wrong number of argument. Why ? how to correct it the to integrate it successfully?

Af := ft + f1*dX + f2*dv + 1/2*f11*dXt + 1/2*f22*dvt + f12*dXvt;
Af := subs(dX = (miu - v/2)*dt, Af);
Af := subs(dv = a*(b - v)*dt, Af);
Af := subs( dXt = v*dt, Af);
Af := subs( dvt = v*(rho^2)*dt, Af);
Af := subs( dXvt = rho*p*v*dt, Af);

Af := subs( ft = (dalpha*y + dbeta)*f, Af);