A=1.2+2.3+3.4+...+2017.2018
3A=1.2.3+2.3.3+3.4.3+...+2017.2018.3
3A=1.2.3+2.3.(4−1)+3.4.(5−2)+...+2017.2018.(2019−2016)
3A=1.2.3+2.3.4−1.2.3+3.4.5−2.3.4+...+2017.2018.2019−2016.2017.2018
⇒3A=2017.2018.2019
⇒A=2017.2018.20193
A=2017.2018.20193;B=201833=2018.2018.20183
A=2739315938;B=2739316611
⇒A<B
B= 1.2 + 3.4 + 5.6 + ... +2017.2018
B= 1.2+3.4+5.6+ ... + 2017.2018
tính các tổng sau:
A=1.2+2.3+3.4+...+n(n+1)
B=1.2.3+2.3.4+...+n(n+1)(n+2)
C=1.2+3.4+5.6+...+2017.2018
D=1.4+2.5+3.6+...+n(n+3)
Giúp mk nha, ai nhanh mk k!
D = 1.2+2.3+3.4+......+2017.2018
Tính nhanh
1.2 + 2.3 + 3.4 + 4.5 + ... + 2017.2018
Tính A = 1.2^2+2.3^2+3.4^2+....+2017.2018^2
S = 1/1.2 + 1/2.3 + 1/3.4 +..........1/2017.2018 + 1/2018.2019
can gap
Tính A= 1+(1+2)+(1+2+3)+........+(1+2+3+.....+2017)/1.2+2.3+3.4+.......+2017.2018
Cho A=1.2+2.3+3.4+4.5+............+2017.2018 va B=2018 mu3/3 So sanh A va B
