a)1/2+1/6+1/12+........+1/9900+1/10100
b)1/2+1/4+1/8+....+1/256+1/512
a)1/2+1/6+1/12+.........+1/9900+1/10100 = ?
b)1/2+1/4+1/8+...........+1/256+1/512 = ?
Tính nhanh:
a)1/2+1/6+1/12+...........+1/1990+1/10100
b)1/2+1/4+1/8+.............+1/256+1/512
(2 + 4 + 6 + ... + 98) x (\(\dfrac{3}{4}\) x 8 - 15 x 0,4) x (\(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + ... + \(\dfrac{1}{512}\) )
Giúp mình vớiii
a) 1/2+1/4+1/8+1/16+....+1/512
b) 1/2+1/6+1/12+1/20+1/30+1/42+1/56+...+1/90+1/110
tinh bang cach thuan tien nhat
1/2+1/6+1/12+1/20
1/2+1/6+1/12+1/20+..........+1/9900
1/2+1/3+1/4+1/8+1/16
1/2+1/3+1/4+1/8+1/16+........+1/512
1/2+1/4+1/8+1/16+...+1/512
1/2+1/6+ 1/12+ 1/20+1/30+.....1/90+ 1/110
trình bày cách làm hộ mình nha!
A= 1/2 + 1/4 + 1/8 +...+1/256 +1/512
1/2+1/3+1/4+...+1/512