31 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 3 + 4 + 15 + 16 + 17 + 18 = 181

31 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 3 + 4 + 15 + 16 + 17 + 18=181

=181 nhé

S>3/15+3/15+3/15+3/15+3/15=15/15=1

S<3/10+3/10+3/10+3/10+3/10=15/10=3/2<2

⇒S ko ϵ N

17+17+17=17x3=41

 S = 3¹⁰ + 3¹¹ + 3¹² + 3¹³ + ....... + 3³¹

Nhân cả hai vế của S với 3 , ta được :

3S = 3 ( 3¹⁰ + 3¹¹ + 3¹² + 3¹³ + ....... + 3^{31 )}

      = 3¹¹ + 3¹² + 3¹³ + ....... + 3³¹ + 3³²

Trừ cả hai vế của S cho 3 , ta được :

3S - S = ( 3¹¹ + 3¹² + 3¹³ + ....... + 3³¹ + 3³² ) - ( 3¹⁰ + 3¹¹ + 3¹² + 3¹³ + ....... + 3^{31 )}

      2S = 3³² - 3¹⁰

=> S = \(\frac{3^{32}-3^{10}}{2}=\frac{3^{10}\left(3^{22}-1\right)}{2}\)

Thank you Đinh Đức Hùng .

3S=3¹¹+3¹²+...+3³¹+3³²

=> 3S-S=(3¹¹+3¹²+...+3³¹+3³²)-(3¹⁰+3¹¹+...+3³¹)=3³²-3¹⁰=3¹⁰.(3²²-1)

=> S=\(\frac{\text{3^{10}.(3^{22}-1)}}{2}\)

uses crt;

var s1:real;

i,n,s2,a:integer;

begin

clrscr;

readln(n);

s1:=1;

for i:=1 to n do s1:=s1*i;

writeln(s1:0:0);

s2:=0;

a:=10;

repeat

s2:=s2+a;

a:=a+1;

until s2>=10000;

writeln(s2);

readln;

end.

\(=\frac{2^{10}\left(3^{31}+2^{30}.3^6\right)}{2^{11}\left(3^{31}+2^{30}.3^6\right)}=\frac{1}{2}\)

ngu rứa S=1

 giờ biết làm rồi chi

(1)          5/2 x (3/4 - 1/3) -11/12+1/4 = 5/2 x (9/12-4/12) -11/12 +3/12=5/2 x 5/12 -11/12 +3/12 = 25/24 - 11/12 +3/12=25/24 -22/24 +                           6/24=9/12=3/4

(2)           11/12 : (4/10 + 3/5) + (5/6 - 1/2) x2/3 

                = 11/12 : (4/10 + 6/10) + (5/6-3/6) x 2/3

                = 11/12:1 +1/2 x 2/3

                = 11/12 + 2/3 =11/12+8/12 = 19/12