Bài 1:
a. (a + sin(x))/sqrt(a*a+x*x+1)
b. -1 <= cos(x) <= 1
Bài 2:
Uses crt;
Var S: String;
i, dc, ds: longint;
Begin
Clrscr;
Write('Nhap xau S: '); readln(S);
dc:=0; ds:=0;
For i:=1 to length(S) do
Begin
If S[i] in ['A'..'Z'] + ['a'..'z'] then inc(dc);
If S[i] in ['0'..'9'] then inc(ds);
End;
Writeln(dc:0:2);
Writeln(ds:0:2);
Readln
End.
Bài 3:
Uses crt;
Var i, n, t: longint;
Begin
Clrscr;
Write('Nhap n = '); readln(n);
t:=0;
For i:=1 to n do if i mod 4 = 0 then t:=t+i;
Writeln(t:0:2);
Readln
End.
