\(tinh:m+1\cdot2+2\cdot3+...+2012\cdot2013\)
ai tra loi nhanh nhat mik tich cho
\(A=\frac{1\cdot2}{2\cdot2}\cdot\frac{2\cdot3}{3\cdot3}\cdot\frac{3\cdot4}{4\cdot4}\cdot\frac{4\cdot5}{5\cdot5}\cdot.................\cdot\frac{2012\cdot2013}{2013\cdot2013}\)với
\(B=\frac{2012\cdot2013-2012\cdot2012}{2012\cdot2011+2012\cdot2}\)
A=\(\frac{1}{2}\).\(\frac{2}{3}\)....\(\frac{2012}{2013}\)=\(\frac{1}{2013}\)
B=\(\frac{2012}{2012.2013}\)=\(\frac{1}{2013}\)
vậy A=B
\(A=\frac{1.2}{2.2}.\frac{2.3}{3.3}.\frac{3.4}{4.4}.\frac{4.5}{5.5}.....\frac{2012.2013}{2013.2013}=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.\frac{4}{5}....\frac{2012}{2013}=\frac{1.2.3.4.5....2012}{2.3.4.5....2013}=\frac{1}{2013}\)
\(B=\frac{2012.2013-2012.2012}{2012.2011+2012.2}=\frac{2012.\left(2013-2012\right)}{2012.\left(2011+2\right)}=\frac{2012}{2012.2013}=\frac{1}{2013}\)
\(\Rightarrow A=B\)
Cho A=\(\frac{1}{1\cdot2}\)+\(\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+.........+\frac{1}{2012\cdot2013}\)
B=\(\frac{2012\cdot2013^{2012}-2012}{20130}\)
Chứng minh rằng: a/b \(\in\)Z
1 + 3 +5 =?
ai tra loi cau hoi nhanh nhat mik tich cho va kb lien
k=\(\frac{1+\left(1+2\right)+\left(1+2+3\right)+...+\left(1+2+3+...+2013\right)}{2013\cdot1+2012\cdot2+2011\cdot3+...+2\cdot2012+1\cdot2013}\)
1+1=
ai tra loi nhanh minh se ket ban voi nguoi đo
ai nhanh nhat minh tich
tra loi cau hoi nay ai duoc loi
tra loi di nha ban
(8x-12)^3=125
phai tra loi dung nhe
ai tra loi nhanh nhat mik tich cho 9 cai luon
nho la ko phai ket qua bang phan so dau nha
( 8 x - 12 ) ^ 3 = 125
( 8 x - 12 ) ^ 3 = 5 ^ 3
=> 8 x - 12 = 5
8 x = 17
x = \(\frac{17}{8}\)
k cho mình đi bạn ơi mình không biết làm đâu~ . ~
\(\left(8x-12\right)^3=125\)
\(\Leftrightarrow\left(8x-12\right)^3=5^3\)
\(\Leftrightarrow8x-12=5\)
\(\Leftrightarrow8x=17\)
\(\Leftrightarrow x=\frac{17}{8}\)
so sánh A=\(\frac{1}{1\cdot2\cdot3}\)+\(\frac{1}{2\cdot3\cdot4}+\frac{1}{3\cdot4\cdot5}+...+\frac{1}{2012\cdot2013\cdot2014}\) với \(\frac{1}{4}\)
Lời giải:
$2A=\frac{3-1}{1.2.3}+\frac{4-2}{2.3.4}+\frac{5-3}{3.4.5}+...+\frac{2014-2012}{2012.2013.2014}$
$=\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+\frac{1}{3.4}-\frac{1}{4.5}+....+\frac{1}{2012.2013}-\frac{1}{2013.2014}$
$=\frac{1}{1.2}-\frac{1}{2013.2014}< \frac{1}{2}$
$\Rightarrow A< \frac{1}{2}:2$
Hay $A< \frac{1}{4}$
CO AI TRAO DOI TICK K ?
(AI TRA LOI NHANH NHAT MINH TICH CHO 2 CAI LUN)
thik thì trao đổi nhưng mà chưa j đã tick cho người khác oy
1+1=
ai tra loi minh se ket ban voi nguoi do
ai nhanh nhat thi minh tich
tra loi cau hoi nay ai cung duoc loi
tra loi di nha cac ban
minh tra loi co chac la ban ket ban voi minh k day
vay thi minh tra loi = 2
nho ket ban voi minh nhe minh da de lai mot cau noi neu ban k ket ban voi minh
1 phut sau loi noi do se hien len sau khi 1 phut troi qua ma ban k ket ban voi minh