A=4^2015+4^2016+4^2017+4^2018
A=(4^2015+4^2016)+(4^2017+4^2018)
A=4^2015.(1+4)+4^2017.(1+4)
A=5.(4^2015+4^2017)
=>A chia hết cho 5
A=4^2015+4^2016+4^2017+4^2018
A=(4^2015+4^2016)+(4^2017+4^2018)
A=4^2015.(1+4)+4^2017.(1+4)
A=5.(4^2015+4^2017)
=>A chia hết cho 5
a. So sanh 2 phan so:A= 2015/2016+2016/2017+2017/2018 va B = 2015+2016+2017/2016+2017+2018
b.1/2.4+1/4.6+........+1/(2x-2).2x = 1/8
c.Cho A = 1/4+1/9+1/16+...+1/81+1/100 . Chung minh rang : A > 65/132
d.Cho B = 12/(2 . 4 ) ^ 2 + 20/ (4 . 6) ^2 + ...........+ 388/ ( 96 . 98 ) ^ 2 + 396/ ( 98 . 100 ) ^2 .Hay so sanh B voi 1 /4
cho A = 2015/2016 + 2016/2017 + 2017/2018 + 2018/2015. Chứng minh A>4
Cho A = 2015/2016+2016/2017+2017/2018+2018/2015
Chứng minh A>4
cho A= 2015/2016 +2016/2017 +2017/2018 +2018/2015. Chứng minh A > 4.
mong các bạn giúp đỡ
ai giúp minh giải bài này với ạ:
A=2015/2016+2016/2017+2017/2018+2018/2015
hãy chứng minh rằng A>4
Chung minh rang: 41^2015+2017^2016+2016^2017+8001^2018 khong phai la so chinh phuong
A= ( 1/2017+ 2/2016+ 3/2015+...+ 2015/3+ 2016/2+ 2017) : ( 1/2+1/3+1/4+...+1/2017+1/2018)
Tính :
S1= 1-2+3-4+....................+2017-2018
S2= 1-4+7-10+..............+2015-2018
S3= 1+2-3-4+.....................+2015+2016-2017-2018
Giup minh voi minh dang can gap nha
ai nhanh ma dungthi minh tich cho nha
cho A = 1/2.3/4.............2016/2017 chung minh A2<1/2018
minh dang can ngay bay gio