Các câu hỏi tương tự
Cho S= 3/1+3/11+3/12+3/13+3/14
Chung minh rang 1<S<2
So sanh phan so 1313/9191va1111/7373
Chung minh rang
A=1/12+1/13+.....+1/22>1/2
B=1/10+1/11+.....+1/99+1/100>1
C=1/5+1/6+1/7+....+1/17<2
D=3/10+3/11+3/12+3/13+3/14
Hoi d co la so tu nhien ko
Cam on cac ban rat nhieu
Chung to rang A=1/8+1/11+1/12+1/13+1/41+1/42+1/43 <1/2
chung minh A=1/11+1/12+...+1/50<8/3
a,A=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2.chung minh rang a<2
b;2^1+2^2+2^3+...+2^30.chung minh rang B chia het cho21
chung minh rang 11^n+2+12^2n+1 chia het cho 133
chung minh rang A=(17^n+1)(17^n+2)chia het cho 3 voi moi n thuoc N
cho (2a+7b) chia het cho 3 ( a b thuoc N). chung to (4a+2b) chia het cho 3
cho C = 1 +3 + 32 + 33 + .... + 311 chung minh rang
a, chứng minh rằng C chia hết cho 13
b, chung minh rang C CHIA HET CHO 40
Câu hỏi: chung minh rang 2 day so nay la hop so a,1+2^7+3^11+5^13+7^17+11^19 b,21^123+23^124+25^125
a.1152 - (374+1152)+(-65+374)
b.13-12+11+10-9+8-7-6+5-4+3+2-1
c. tinh tong S = 1.2 + 2.3 + 3.4 + ..... + 99.100
d. chung minh rang : 1/22+1/32 +1/42 + ..... + 1/1002 < 1