\(A=\frac{1}{1+2}+\frac{1}{1+2+3}+...+\frac{1}{1+2+..+100}\)
\(=\frac{2}{2.3}+\frac{2}{3.4}+\frac{2}{4.5}+..+\frac{2}{100.101}=2\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+..+\frac{1}{100}-\frac{1}{101}\right)\)
\(=2\left(\frac{1}{2}-\frac{1}{101}\right)=\frac{99}{101}\)
Tính
a) (x-1/2)+(x-1/4)+(x-1/8)+...+(x-1/512)
Tìm x
a) (x-1/1×2)+(x-1/2×3)+...+(x-1/100×101)
b) (x-1)+(x-2)+(x-3)+...+(x-101)=5050
c) x+1/2+1/3+1/4+...+1/100=3/2+4/3+5/4++...+101/100
Tính A:B
a)A=98+1/2+1/3+1/4+...+1/99
B=2/3+4/3+5/4+...+100/99
b)A=2018+1/2+1/3+1/4+...+1/2019
B=3/2+4/3+3/4+...+2020/2019
c)A=99/1+98/2+97/3+...+2/98+1/99
B=1/2+1/3+1/4+...+1/100
Giải đầy đủ
Tính A = 3+ 3/1+2 + 3/1+2+3 + 3/ 1+2+3+4 + .........+3/1+2+3+4+...+100
A=1+1*2+1*2*3+1*2*3*4+...+1*2*3*...*100
A= 3/1 +3/1+2+3/1+2+3 + 3/1+2+3+4 +...+ 1/1+2+3+4+...+100
ai làm đúng mình tick mình đang vội nhanh hộ mình
A= 3/1 +3/1+2+3/1+2+3 + 3/1+2+3+4 +...+ 1/1+2+3+4+...+100
ai làm đúng mình tick mình đang vội nhanh hộ mình
1+1/2*2+1/3*3+1/4*4+.....+1/99*99+1/100*100
a ko phai bằng số tự nhiên
Tính nhanh
a.(1+1/2)×(1+1/3)×(1+1/4)×...×(1+1/98)×(1+1/99).
b.1/2×2/3×3/4×...×97/98×98/99×99/100
tính nhanh
a) a= ( 1-1/11) * ( 1-1/12) * ,,,,,, *( 1- 1/100)
b) b= 1+ 2/2*3+2/3*4+,,,,,+2/198*199+2/199*100
C,1/1*2+1/2*3+1/3*4+1/4*5
D,2/1*3+2/3*5+2/3*7+......................2/19*21
E,1/1*4+1/4*7+ 1/7*10+.........................2/100*103
