cho A=(1/2^2-1).(1/3^2-1).(1/4^2-1).....(1/100^2-1). So sanh A voi 1/2
A=(1/2^2-1) * (1/3^2-1) *...*(1/100^2-1) so sanh A voi 2
A=(1/2^2-1) * (1/3^2-1) *...*(1/100^2-1) so sanh A voi 1/2
so sanh A= 1/2^2 + 1/ 3^2 +1/4^2+...+ 1/300^2 voi 3/4
so sanh
A = 1+ 1/2 + (1/2)2+ (1/2)3+ ...+ (1/2)100 voi B = 2
so sanh A va B voi 0
A = 1. ( - 2 ) . 3 . ( - 4 ) ..... . 99 . ( -100 )
B = 1 . ( - 2 ) . 3 . ( - 4 ) . ... . (-98) . 99
Cho A=\(\left(\frac{1}{2^2}-1\right).\left(\frac{1}{3^2}-1\right).\left(\frac{1}{4^2}-1\right).....\left(\frac{1}{100^2}-1\right)\)
So sanh A voi \(\frac{1}{2}\)
Cho S=1+3^2+3^4+3^6+.......+3^98+3^100.
So sanh 8S+1 voi 2^152
Tim so du cua S khi chia cho 10.
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
