Okay...I cannot for the life of me figure out what is wrong with my code.
The functions finalgrade and needgrade are supposed to reverse one another,
but this is not what happens when I actually execute them. If anyone can
read Maxima program code, I would be interested if they could tell me where
I went wrong (unless it's a Maxima issue). finalgrade seems to be all right;
the problem could be the if part of needgrade. This is pretty discouraging,
especially considering that I haven't programmed in Maxima for very long.
load(descriptive);
drop (L,n) := if n=1 then delete(mini(L),L,1) else drop(drop(L,n-1),1);
replace (L,x) := if x>mini(L) then cons(x,drop(L,1)) else L;
finalgrade (dq,midterm,final) := ([fg],
dq: drop(dq,2),
midterm: replace(midterm,final),
fg: 3*sum(dq[i],i,1,13)/13+(midterm[1]+midterm[2])/5+3*final/10,
if fg>=89.5 then print("student got an A")
elseif fg>=84.5 then print("student got a B+")
elseif fg>=79.5 then print("student got a B")
elseif fg>=74.5 then print("student got a C+")
elseif fg>=69.5 then print("student got a C")
elseif fg>=66.5 then print("student got a D+")
elseif fg>=59.5 then print("student got a D")
else print("student got an F"), fg)$
needgrade (dq,midterm,desired) := ([need,lower,cutoff],
dq: drop(dq,2),
lower: lmin(midterm),
cutoff: 3*sum(dq[i],i,1,13)/13+(midterm[1]+midterm[2])/5+3*lower/10,
if desired>cutoff then block(
drop(midterm,1),
need: 2*(desired-3*sum(dq[i],i,1,13)/13-midterm[1]/5))
else need:
10/3*(desired-3*sum(dq[i],i,1,13)/13-(midterm[1]+midterm[2])/5),need)$