1/2 + 1/2 + 1+1
= ( 1/2 + 1/2) + 2
= 1+ 2
= 3
1/2+1/2+1+1
=1+1+1
=2+1
=3
tích mình mình tích lại
G=(1-1/2^2).(1-1/3^2).(1-1/4^2).......(1-1/100^2)
H=(1-1/2^2).(1-1/3^2).(1-1/4^2)........(1-1/2018^2)
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)
1^2/1x2x2^2/2x3x4^2/3x5............20^2/19x21 đề bài là tính tích
Bài 2 : Tính tích A = ( 1- 1/1+2)(1-1/1+2+3)(1-1/1+2+3+4).........(1-1/1+2+........+2020)
B = (1/2-1/3)(1/2-1/5)(1/2-1/7).......(1/2-1/99)
Tính:
A=(1-1/1+2).(1-1/1+2+3).(1-1/1+2+3+4)...(1-1/1+2+3+4+...+2022)
B=1+1/2(1+2)+1/3(1+2+3)+1/100(1+2+3+...+100)
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
1/ cmr:1/2*5+1/5*8+...+1/(3n-1)(3n-2)=n/6n+4
2/ tính:
A=1/2-1/2^2+1/2^3-1/2^4+1/2^5-...+1/2^99-1/2^100
B=(1/2+1)(1/3+1)(1/4+1)...(1/99+1)
Tính nhanh:\(\frac{1^2+1}{2^2+1}+\frac{1^2-1}{2^2-1}-\frac{2^2+1}{3^2+1}+\frac{2^2-1}{3^2-1}+...-\frac{1999^2+1}{2000^2+1}+\frac{1999^2-1}{2000^2-1}\)
chứng tỏ rằng
b= 1/2^2+1/3^2+1/4^2+1/5^2+1/6^2+1/7^2+1/8^2<1
b tính nhanh
A= 1+1/2(1+2) +1/3(1+2+3)+1/4(1+2+3+4)+...+ 1/16(1+2+3+...+16)
a) chứng tỏ rằng: B= 1/2^2+ 1/3^2 + 1/4^2 + 1/5^2 +1/6^2 + 1/7^2+ 1/8^2<1
b) A= 1+1/2(1+2)+1/3(1+2+3)+1/4(1+2+3+4)+...+1/16(1+2+3+.....+16)
Ai nhanh mk tick
1. (1+1/2).(1+1/2^2).(1+1/2^3)....(1+1/2^100) < 3
2. 1/(5+1)+2/(5^2+1)+4/(5^4+1)+...+ 1024/(5^1024+1) <1/4
3. 3/(1!+2!+3!)+4/(2!+3!+4!)+...+100/(98!+99!+100!) <1/2
