Cau1.Hay tinh hop li cac tong sau daya) A1/3+1/3^2+1/3^3+....+1/3^100b)B10/56+10/140+10/260+....+10/1400Cau2Cho C2+2^2+2+3+...+2^99+2^100a)Tinh tong Cb)Tim x de2^2x-1-2C c)Chung minh rang C chia het ch 31Cau 3a) So sanh: A2005^2005+1/2005^2006+1 va B2005^2004+1/2005^2005+1b)Tim so nguyen m sao cho so m+6/m-1 la so nguyenCau4Cho ABx(cm) AC7(cm) BC2x-1(cm) .Timx sao cho ba diem A B C thang hangCau 5a) Tim x,y thuoc N biet 2^x+6245^yb)Voi gia tri nao cua x ,y thi bieu thuc A/x-y/+/x+1/+2013...
Đọc tiếp
Cau1.Hay tinh hop li cac tong sau day
a) A=1/3+1/3^2+1/3^3+....+1/3^100
b)B=10/56+10/140+10/260+....+10/1400
Cau2
Cho C=2+2^2+2+3+...+2^99+2^100
a)Tinh tong C
b)Tim x de2^2x-1-2=C
c)Chung minh rang C chia het ch 31
Cau 3
a) So sanh: A=2005^2005+1/2005^2006+1 va B=2005^2004+1/2005^2005+1
b)Tim so nguyen m sao cho so m+6/m-1 la so nguyen
Cau4
Cho AB=x(cm) AC=7(cm) BC=2x-1(cm) .Timx sao cho ba diem A B C thang hang
Cau 5
a) Tim x,y thuoc N biet 2^x+624=5^y
b)Voi gia tri nao cua x ,y thi bieu thuc A=/x-y/+/x+1/+2013 dat gia tri nho nhat .Tim gia tri nho nhat do
Chu y dau ''/'' la dau gia tri tuyet doi
Cau 6
De chuan bi cho ki thi hoc sinh gioi, mot hoc sinh giai 35 bai toan.Biet rang cu moi bai dat loai gioi duoc thuong 20 diem moi bai dat loai kha trung binh duoc thuong 5 diem . Con moi bai yeu, kem bi tru 10. Lam xong 35 bai em do duoc thuong 130 diem .Hoi co bao nhieu bai loai gioi ,bao nhieu bai loaiyeu ,kem .Biet rang co8 bai kha va trung binh
Ai lam dung minh tich cho
Nho giai ra nha
