A = 2/3 + 2/9 + 2 /27 + 2/81 + 2/243 + 2 /729
B = 1 /3 + 1/12 + 1/48 + 1/192 + 1/768
MK QUÊN VT ĐỂ BÀI ĐỂ BÀI LÀ : TÍNH NHÉ !
1.Tính tổng:
a,1/3+1/9+1/27+1/81+1/243+1/729.
b,2/3++2/6+2/12+2/24+2/48+2/96+2/192.
HÃY GIẢI BẰNG 3 CÁCH! AI LÀM ĐÚNG MỖI NGÀY MÌNH SẼ TÍCH!
BÀI TÍNH NHANH
A.2/3+2/6+2/12+2/24+2/48+2/96+2/192
B.1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
C.1/3+1/9+1/27+1/81+1/243+1/729
D.3/2+3/8+3/32+3/128+3/512
E.3+3/5+3/25+3/125+3/625
a) = \(\frac{127}{96}\)
b) = \(\frac{255}{256}\)
c) Mik bỏ nha
d) = \(\frac{1023}{512}\)
e) = \(\frac{2343}{625}\)
Bài 1: Tính nhanh
a) 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/128 + 1/256
b) 1/3 + 1/9 + 1/27 + 1/81 + 1/243 + 1/729
c)1/2 + 1/6 + 1/12 + 1/20 + 1/30
tính bằng 2 cách
nhanh nhé
bài 1 tính nhanh
mik xin sửa đề câu a thành thế này ~
\(a,\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}+\frac{1}{256}\)
đặt \(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}+\frac{1}{256}\)
\(A\cdot2=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\)
\(A\cdot2-A=\) ( \(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}\) ) - ( \(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}+\frac{1}{256}\) )
\(A=1-\frac{1}{256}\)
\(A=\frac{255}{256}\)
\(b,\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}+\frac{1}{243}+\frac{1}{729}\)
đặt \(B=\) \(\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}+\frac{1}{243}+\frac{1}{729}\)
\(B\cdot3=1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}+\frac{1}{243}\)
\(B\cdot3-B=\) ( \(1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}+\frac{1}{243}\)) - \(\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}+\frac{1}{243}+\frac{1}{729}\) )
\(B\cdot2=\) \(1-\frac{1}{729}\)
\(B\cdot2=\frac{728}{729}\)
\(B=\frac{728}{729}:2\)
\(B=\frac{364}{729}\)
\(c,\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)
ĐẶT \(C=\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)
\(C=\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+\frac{1}{5\cdot6}\)
\(C=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)
\(C=\frac{1}{1}-\frac{1}{6}\)
\(C=\frac{5}{6}\)
tính nhanh :Bài 1: 1/3+1/9+1/27+1/81+1/243+1/729
Bài 2 : 1+5/4+5/8+5/16+5/32+5/64
Bài 3: 3/2+3/8+3/32+3/128+3/512
Bài 4: 3+3/5+3/25+3/125+3/625
Bài 5: 1/5+1/10+1/20+1/40+.........+1/1280
Bài 6: 1/3+1/9+1/27+1/81+.............+1/59049
Mk mong các bn giúp đỡ hãy lm đúng cho mk nha~mk cần rất gấp sáng mai rùi nha~
Bài 1: 1/3+1/9+1/27+1/81+1/243+1/729
Đặt:
A = 1 + 1/3 + 1/9 + 1/27 + 1/81 + 1/243 + 1/729
Nhân A với 3 ta có:
\(Ax3=3+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}+\frac{1}{243}\)
\(\Rightarrow Ax3-S=3-\frac{1}{243}\)
\(\Rightarrow2A=\frac{2186}{729}\)
\(\Rightarrow A=\frac{2186}{729}:2\)
\(\Rightarrow A=\frac{1093}{729}\)
Bài 2Câu hỏi của nguyễn phạm mimi - Toán lớp 6 | Học trực tuyến
Bài 3
nguồn:Tính nhanh: 3/2 + 3/8 + 3/32 + 3/128 + 3/512
Bài 4Câu hỏi của VŨ THỊ MAI CA - Toán lớp 4 - Học toán với OnlineMath
Bài 5Câu hỏi của Phạm Dora - Toán lớp 4 - Học toán với OnlineMath
Bài 6 Câu hỏi của huỳnh thị thu uyên - Toán lớp 5 - Học toán với OnlineMath
tính nhanh
a) 1/2+1/4+1/8+1/16+1/32
b) 1/3+1/9+1/27+1/81+1/243+1/729
A = \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) + \(\dfrac{1}{32}\)
2 \(\times\) A = 1 + \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\)
2 \(\times\) A - A = 1 + \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) - (\(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) + \(\dfrac{1}{32}\))
A = 1 + \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) - \(\dfrac{1}{2}\) - \(\dfrac{1}{4}\) - \(\dfrac{1}{8}\) - \(\dfrac{1}{16}\) - \(\dfrac{1}{32}\)
A = 1 - \(\dfrac{1}{32}\)
A = \(\dfrac{31}{32}\)
B = \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\) + \(\dfrac{1}{729}\)
3 \(\times\)B = 1 + \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\)
3 \(\times\) B - B = 1 + \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\) -(\(\dfrac{1}{3}\)+\(\dfrac{1}{9}\)+\(\dfrac{1}{27}\)+...+\(\dfrac{1}{729}\))
2B = 1 + \(\dfrac{1}{3}\) + \(\dfrac{1}{9}\) + \(\dfrac{1}{27}\) + \(\dfrac{1}{81}\) + \(\dfrac{1}{243}\) - \(\dfrac{1}{3}\) - \(\dfrac{1}{9}\)-\(\dfrac{1}{27}\)-...- \(\dfrac{1}{729}\)
2B = 1 - \(\dfrac{1}{729}\)
2B = \(\dfrac{728}{729}\)
B = \(\dfrac{728}{729}\) : 2
B = \(\dfrac{364}{729}\)
Tìm x : x*1/4=6:1/2
Tính nhanh : 2/3+2/9+2/27+2/81+2/243+2/729
4/5+1/2-1/6
Tính
\(x\) \(\times\) \(\dfrac{1}{4}\) = 6 : 1 : 2
\(x\) \(\times\) \(\dfrac{1}{4}\) = 6:2
\(x\) \(\times\) \(\dfrac{1}{4}\) = 3
\(x\) = 3 : \(\dfrac{1}{4}\)
\(x\) = 12
Mình nhầm đoạn 6:1/2.nhờ bạn giải lại hộ mình với
\(x\)\(\times\) \(\dfrac{1}{4}\) = 6 : \(\dfrac{1}{2}\)
\(x\) \(\times\) \(\dfrac{1}{4}\) = 6 \(\times\) \(\dfrac{2}{1}\)
\(x\) \(\times\) \(\dfrac{1}{4}\) = 12
\(x\) = 12 : \(\dfrac{1}{4}\)
\(x\) = 48
Tính nhanh:
A = \(\dfrac{2}{3}\) + \(\dfrac{2}{9}\) + \(\dfrac{2}{27}\) + \(\dfrac{2}{81}\) + \(\dfrac{2}{243}\) + \(\dfrac{2}{729}\)
A \(\times\) 3 = 2 + \(\dfrac{2}{3}\) + \(\dfrac{2}{9}\) + \(\dfrac{2}{27}\) + \(\dfrac{2}{81}\) + \(\dfrac{2}{243}\)
A \(\times\) 3 - A = 2 - \(\dfrac{2}{729}\)
A \(\times\) ( 3 - 1) = 2 \(\times\) ( 1 - \(\dfrac{1}{729}\))
A \(\times\) 2 = 2 \(\times\) \(\dfrac{728}{729}\)
A = 2 \(\times\) \(\dfrac{728}{729}\) : 2
A = \(\dfrac{728}{729}\)
c, tính:
\(\dfrac{4}{5}\) + \(\dfrac{1}{2}\) - \(\dfrac{1}{6}\)
= \(\dfrac{4}{5}\) + \(\dfrac{1}{3}\)
= \(\dfrac{17}{15}\)
tính nhanh:
a, 5/2 + 5/6 + 5/18 + 5/54+5/162+5/486
b, 2/3+2/6+2/12+2/24+2/48+2/96+2/192
c, 1/3+1/9+1/27+1/81+1/243+1/729
d, 3/2+3/8+3/32+3/128+3/512
e, 1/2.3+1/3.4+1/5.6+1/6.7+1/7.8
g, 4/3.7+4/7.11+4/11.15+4/15.19+4/19.23+4/23.27
h, 2/2.5+2/5.8+2/8.11+2/11.14+2/14.17
i, 4/1.3.5+4/3.5.7+4/5.7.9+4/7.9.11+4/9.11.13+4/11.13.15
k,2/1.2.3+2/2.3.4+2/3.4.5+2/4.5.6+2/5.6.7+2/6.7.8
bài 1 : tính nhanh tổng:
1+1/3+1/9+1/27+1/81+1/243+1/729
1 + 1/3 + 1/9+1/27+1/81+1/243+1/729
=1+1-1/3+1/3-1/9+1/9-1/27-1/27-1/81+1/81-1/243
= 2 - 1/243
=485/243
Bài 1 : Tính:
a, | 20. 24 + 12 . 24 - 48 . 22 | : 82 Cái này | là ngoặc tròn nha , phím tui bị liệt
b, | 75 . 54 + 175 . 54 | : | 20 . 25 . 125 - 625 . 75 |
Bài 2:
a, Cho A = 5 . 415 . 99 - 4 . 3020 . 89
B = 5 . 29 . 619 - 7 . 229 . 276
Tính A ; B.
b, cho C = 2181 . 729 + 243 . 81 . 27
D = 32 . 92 . 243 + 18 . 243 . 324 + 723 . 729
Tính C; D.
Bài 3 : Tính
a, 100 - [ 75 - | 7- 2 |2 ]
b, | 23 . 94 + 94 . 45 | : 92 . 10 - 92 |
Bài 4 :Tìm x biết
a, 390 - | x - 7 | = 169 : 13
b, | x - 140 | : 7 = 33 - 23 . 3
c, x - 6 : 2 - | 48 - 24 | : 2 : 6 - 3 = 0
d, x + 5 . 2 - | 32+ 16 . 3 : 6 - 15 | = 0
Phiền các bạn giải nhanh giúp mk nha