Lời giải:
Bài 1:
program hotrotinhoc;
var P: longint;
i,n: integer;
begin
write('n='); readln(n);
P:=1;
for i:=3 to n do
P:=P*i;
write(P);
readln
end.
Bài 2:
program hotrotinhoc;
var S: longint;
i,n: integer;
begin
write('n='); readln(n);
S:=1;
for i:=6 to n do
S:=S*((2*i)+1);
write(S);
readln
end.
Bài 3:
rogram hotrotinhoc;
var P: longint;
i,n: integer;
begin
P:=1;
for i:=6 to n do
P:=P*(2*i);
write(P);
readln
end.
Bài 4:
rogram hotrotinhoc;
var S: longint;
i,n: integer;
begin
P:=1;
for i:=1 to n do
P:=P*(1/(((2*n)+1)*((2*i)+3));
write(P);
readln
end.