Các câu hỏi tương tự
chung to rang 1/5+1/6+1/7=...+1/16+1/17<2
BAI 1: chung to rang 175 + 244 + -1321 chia het cho 10
BAI 2:chung minh rang voi moi so tu nhien n :
a) 74n -1 chia het cho 5
b) 34n+1 +2 chia het cho 5
chung to rang B=1/2^2+1/3^2+1/4^2+1/5^2+1/6^2+1/7^2+1/8^2<1
ai lam duoc minh tick cho
chung to rang B= 1/2^2+1/3^2+1/4^2+1/5^2+1/6^2+1/7^2+1/8^2<1
Cho B=1/4+1/5+1/6+...+1/19.Hay chung to rang B>1
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
a) cho A = 1 + 3 + 5 + 7 +......+(2n + 1) Voi n thuoc N
chung to rang A la so chinh phuong
b) cho B = 2 +4+6 + 8 + ....+ 2n Voi n thuocN
so B co the la chinh phuong ko
chung minh rang B= 1/5+1/6+1/7+.....+1/19<11/6
biet A =717+17x3 -1 la so chia het cho 9.Co the su dung ket qua nay de chung to rang B= 718 +18x3-1 cung chia het cho 9 khong