pro FUNCT,x,a,f,pder

nx=n_elements(x)
na=n_elements(a)
pder=fltarr(nx,na)

f=replicate(a(na-1),nx)
for i=na-2,0,-1 do f=f*x+a(i)

for j=0,na-1 do for i=0,nx-1 do if j eq 0 then pder(i,j)=1. else $
                                   pder(i,j)=x(i)^j

return
end