Bài 1 

a, Tính P=1+1/2(1+2)+1/3(1+2+3)+1/4(1+2+3+4)+....+1/2012(1+2+3+...+2012)

b,Tìm x thỏa mãn 4^5+4^5+4^5+4^5/3^5+3^5+3^5.6^5+6^5+6^5+6^5+6^5+6^5/2^5+2^5=2^x

Cho S =1/5+2/5²+3/5³+4/5⁴+.......+2012/5²⁰¹²

So sánh S với 1/3

Cho S =1/5+2/5 mu 2 +3/5mu 3 +4/5 mu 4+....+2012/5 mu 2012 

So sánh S với 1/3

Tính

A=1-5^2+5^4+5^6+5^8-...+5^100

B= 1/3+(1/3)^2+(1/3)^3+...+(1/3)^2012

CMR : 1/5^2-1/5^4+1/5^6-1/5^8+.................+1/5^2014-1/5^2012 <1/26

Chứng minh S =1/5^2 -1/5^4+1/5^6-...+1/5^4n-2+...+1/5^2010-1/5^2012<1/26

tính:  \(A=\frac{1}{5}-\frac{1}{5^2}+\frac{1}{5^3}-\frac{1}{5^4}+...+\frac{1}{5^{2011}}-\frac{1}{5^{2012}}\)= ?

a/48.2012+2012+2012
b/15/16:3/8.3/4
c/1234.1236-1/1233+1234x1235
B.2/tim X
a/x:36-5=12
b/22/5:x=44/5:5/2
c/8,35.x+6,65.x=45
d/3/5-x+1/3=1/4

bai 1 

1) (-3)^10 . 15^5 / 25^3 . (-9)^7

2) (-5)^60 . 30^5 / 15^5 . 5 ^61

3) 3/5+ 3/5^3 + 3/5^5 + ...  + 3/5^ 199

4) 3^6 . 45^4 - 15^13 . 5^-9   /   27^4 . 25^3 + 45^6

bai 2 ; so sanh

1) (-5)^30 ; (-3) ^50

2) ( -1/16)^10  ; (1/2)^50

3) 2^2010+1 / 2^2007 + 1    ;    2^2012+1   / 2^2009+1