2 + 1 =
A=1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+...(1000) số 1
B=2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+...+2(13512 số 2)
tổng của A và B là
1+1+1+1+1+1+1+1+1+1+1:0=?
2+2+2+2+2+2+2+2+2+2×2÷1=?
a) không tính đươc vì ko có kết quả của 1:0
b) 22
nhớ tkkkkkkkkkkkk
(1+2/1)*(1+2/2)*(1+2/3) *(1+2/4)*(1+2/5)*(1+2/6)*(1+2/7)*(1+2/8)*(1+2/9)*(1+2/11)*(1+2/12)*...............*(1+2/26)*(1+2/27) = ?
Chứng Minh Rằng:
P=(1+1/a^2+1/(a+1)^2)^1/2=1+1/a-1/a-1
Tính :S=(1+1/1^2+1/2^2)^1/2+(1+1/2^2+3^2)^1/2+...+(1+99^2+100^2)^1/2
tính(1+2/1)(1+2/2)(1+2/3).....(1+2/26)(1+2/27)
(1-1/2^2)(1-1/3^2)(1-1/4^2)........(1-1/2007^2)
1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2+1+2=
5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5+5=
...................=66
...................=110
1+2+........+1+2 = 66
5+5+........+5+5 = 220
k mk nha
nhận xét dùm coi mk làm đúng không nha :
Rút gọn biểu thức A=1+1/2+1/2^2+1/2^3+...+1/2^2012
=> 2A = 1/2^1+1/2^2+...+1/2^2012+1/2^2013
=> 2A - A = 1A =(1/2^1+1/2^2+...+1/2^2012+1/2^2013)-(1/2^0+1/2^1+1/2^2+1/2^3+...+1/2^2012)
=> 1A = 1/2^2012-1/2^0
= 1/2^2012-1/1
mấy bạn coi ntn
cách này ngon hơn nè
\(2A=2\left(1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{2012}}\right)\)
\(2A=2+1+\frac{1}{2}+...+\frac{1}{2^{2011}}\)
\(2A-A=\left(2+1+\frac{1}{2}+...+\frac{1}{2^{2011}}\right)-\left(1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{2012}}\right)\)
\(A=2-\frac{1}{2^{2012}}\)