C=1/2+1/4+1/8+1/16+1/32+1/64+1/128
C=1-1/2+1/2-1/4+1/4-1/8+1/8-1/16+1/16-1/32+1/32-1/64+1/64-1/128
C=1-1/128
C=127/128
D=1/2+1/6+1/12+1/20+1/30+1/42
D=1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+1/6.7
D=1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
D=1/1-1/7
D=6/7
B= 6/1.3+6/3.5+6/3.7+......+6/97.99
C=1/2 + 1/6 + 1/12 + 1/ 20 + 1/30 + 1/42
D= 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
Giúp mik vs nha mn ^^
Tính nhanh
A=1/2+1/6+1/12+1/20+1/30+1/42
B=1/2+1/4+1/8+1/6+1/32+1/64
1)1/2+1/22+1/23+....+1/22004
2)1/2+1/4+1/8+1/16+1/32+1/64
3)1/6+1/12+1/20+1/30+1/42+1/56
tính nhanh:
a)1/2+1/6+1/12+1/20+1/30+1/42
b)1/2+1/4+1/8+1/16+1/32
c)1/2+1/4+1/8+...+1/256
1)Tính:
a) A=1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90
b) B=(3/4)(8/9)(15/16)(24/25)(35/36)(48/49)(63/64)
c) C=1/4+1/12+1/36+1/108+1/324+1/92
bài 1 : 1/1x2+1/2x3+1/3x4+1/5x6+1/6x7
Bài 2:1/2+1/6+1/12+1/30+1/42+1/56+1/72
Bài 3: (1-1/2)x(1-1/3)x....x(1-2019)
Bài 4:1/4+1/8+1/16+1/32+1/64+1/128+1/256+1/512
1 Tính nhanh
a,1\5+4\10+9\15+16\20+36\30+64\40+81\45
b,1\2+1\6+1\12+1\20+1\30+1\42+1\50+1\72+1\90
bài 2: tính nhanh :
a) 3/8 + 7/12 + 10/16 + 10/24 b) 4/6 + 7/13 + 17/9 + 19/13 + 1/9 + 14/6
c) 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56
Bài 2: Tìm các số tự nhiên x, y biết
a) (x-3)(y+5)=13
b) (8-2x)(11-5y)=0
c) (3x-1)(y+2)=16
d) x-3=y(x-1)
Mn giải thích đầy đủ giúp mình với ạ, mình cảm ơn
