Var a, b, c, s, k: real;
begin
readln(a, b, c, k);
s := ((a * b - c * k) * a) / (b * b - a * c);
writeln('S = ', S);
writeln('F(S) = ', sin(3.14 / 6) - 0.5 * S / (a * b * c));
end.
2)
var l, m, n, k: real;
begin
readln(l, m, n);
k := (l - n) / (l * n) * n;
if ((k < 0) or (k > 1)) then
begin
writeln('X = ', (sqr(l) - n) / m);
writeln('Y = ', k * (l - m) / l);
end
else
begin
writeln('X = ', (k * l * m) / n);
writeln('Y = ', l * m * k);
end;
end.