D=1.2+2.3+3.4+...+2017.2018
=>3D=1.2.3+2.3.3+3.4.3+...+2017.2018.3
=>3D=1.2.(3-0)+2.3.(4-1)+3.4.(5-2)+...+2017.2018.(2019-2016)
=>3D=1.2.3-0.1.2+2.3.4-1.2.3+3.4.5-2.3.4+...+2017.2018.2019-2016.2017.2018
=>3D=2017.2018.2019/3
=>D=2739315938
k mk nha $_$
:D
Tính A = 1.2^2+2.3^2+3.4^2+....+2017.2018^2
Tính A= 1+(1+2)+(1+2+3)+........+(1+2+3+.....+2017)/1.2+2.3+3.4+.......+2017.2018
Tính:
\(A=1.2^2+2.3^2+3.4^2+.....+2017.2018^2\)
Tính A=1+(1+2)+(1+2+3)+....+(1+2+3+.....+2017)/1.2+2.3+3.4+......+2017.2018
.Tính:
A=1.2^2+2.3^2+3.4^2+...+2017.2018^2
Dau "." là dấu nhân nha các bạn
Tính tổng \(A=\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{2017.2018}\)
(1.2+2.3+......+2017.2018+2018.2019)-(1 mũ2+2 mũ2+.......+2017 mũ2 +2018 mũ 2
1.22+2.32+3.42+...+2016.20172+2017.20182
a,1/1.2 + 1/2.3 + 1/ 3.4+....+ 1/2017.2018
b, 2/3.5+ 2/ 5.7 + 2/7.9 +....+ 2/.91.99
Ai giúp mink tích cho!
