Ta co
1/1+2=2/2.3
1/1+2+3=2/3.4
=>1/1+2+3+....+99=2/99.100
=>1/1+2+1/1+2+3+....+1/1+2+3+...+99
=2/2.3+2/3.4+....2/99.100
=2(1/2.3+1/3.4+....1/99.100)
=2(1/2-1/100)
=2.49/100=49/50
=>a=49/50+1/50=1
TICK CHO TAO NHA
mot qua dua nang 4kg, biet gia cua 1kg dua 12000 dong, ban An muon mua 1/2 qua dua do thi phai tra so tien la bao nhieu?Biet rang cua hang co the cat nho qua dua de ban
CMR: C=1/3+1/32+1/33+...+1/399 nho hon 1/2
cho hàm số y=f(x)=x^2-2. co tat ca bao nhieu diem duoi day thuoc do thi ham so: A(0;-2), B(-1;-3), C(1;-3)
(1/2)+(1/2)^2+(1/2)^3+......(1/2)^99
băng bao nhiêu
M = 1+ 1/2 . ( 1+2) + 1/3.(1+2+3)+....+ 1/99.(1+2+3+...+99)
b=1/2+(1/2)^2+(1/3)^3+....++(1/2)^98+(1/2)^99+(1/2)^99
mot nhom may khoan gom 3 do , doi 1 hoan thanh trong 3h , doi 2 hoan thanh trong 4h , doi 3 hoan thanh trong 5h. hoi moi doi co bao nhieu cong nhan biet tong so cong nhan moi doi la 94.
mik lam mai ko ra nen nho moi nguoi, giup mik nha, mik can gap lam !!!!!
