1+(1+2)+(1+2+3)+(1+2+3+4)+...+(1+2+3+...+2017)
Tính S = 1 + 1/2.(1 + 2) + 1/3.(1 + 2 +3) + 1/4.(1 + 2 +3 + 4) +....+ 1/2017.(1 + 2 + 3 +...+ 2017)
1+1/2×(1+2)+1/3×(1+2+3)+1/4×(1+2+3+4)+....+1/2017×(1+2+3+....+2017)
( 1-1/2) . (1-1/3).(1-1/4).......(1-1/2016) . (1-1/2017)
=1/2.2/3.3.4x...x2015/2016.2016/2017
=1.2.3.4. ... .2015.2016/2.3.4.5. ... .2016.2017
(giống nhau you gạch đi )
=1/2017
1+1/2×(1+2)+1/3×(1+2+3)+1/4×(1+2+3+4)+....+1/2017×(1+2+3+....+2017)
( 1-1/2) . (1-1/3).(1-1/4).......(1-1/2016) . (1-1/2017)
=1/2.2/3.3.4x...x2015/2016.2016/2017
=1.2.3.4. ... .2015.2016/2.3.4.5. ... .2016.2017
giống nhau you gạch đi cả hai bên số đó
=1/2017
nhé !
1/1 nhân 1/2 +1/2 nhân 1/3 +1/3 nhân 1/4 +... +1/2016 nhân 1/2017
TÍnh
S=1+1/2(1+2)+1/3(1+2+3)+1/4+(1+2+3+4)+.....+1/2017(1+2+3+...+2017)
Tính tổng \(S=\frac{1}{1^4+1^2+1}+\frac{2}{2^4+2^2+1}+\frac{3}{3^4+3^2+1}+...+\frac{2017}{2017^4+2017^2+1}\)
Cho biểu thức : B = 2017+2017/1+2+2017/1+2+3+2017/1+2+3+4+....+2017/1+2+3+...+2012
Tính tổng \(S=\dfrac{1}{1^4+1^2+1}+\dfrac{2}{2^4+2^2+1}+\dfrac{3}{3^4+3^2+1}+...+\dfrac{2017}{2017^4+2017^2+1}\)
A= ( 1/2017+ 2/2016+ 3/2015+...+ 2015/3+ 2016/2+ 2017) : ( 1/2+1/3+1/4+...+1/2017+1/2018)
Chứng minh rằng F= 1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+...+1/(1+2+3+4+5+6+...+2017)<2016/2017
1/1×2 + 1/2×3 + 1/3×4 + 1/4×5 +.....+1/2017×2017
\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+....+\frac{1}{2017.2018}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2017}-\frac{1}{2018}\)
\(=\frac{1}{1}-\frac{1}{2018}\)
\(=\frac{2017}{2018}\)
= 1/1- 1/2+...+1/2017-1/2018
=1-1/2018
=2017/2018
k mk nha các bạn
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2016}-\frac{1}{2017}\)
\(=\frac{1}{1}-\frac{1}{2017}=\frac{2016}{2017}\)
cho b= 1+1^2+1^3+1^4+......+^2017 tìm tổng dãy số
cho b=2+2^2+2^3+....+2^2017. tim tổng dãy số
cho b =3+3^2+3^3+.....+2^2017 .tìm tổng dãy số
\(B=1+1^2+1^3+.......+1^{2017}\)
\(1.B=1^2+1^3+....+1^{2018}\)
\(1B-B=1^{2018}-1\)
\(B.0=1^{2018}-1\)
\(B=2+2^2+2^3+.....+2^{2017}\)
\(2B=2^2+2^4+.....+2^{2018}\)
\(2B-B=2^{2018}-2\)
\(B=\frac{2^{2018}-2}{1}\)
\(B=3+3^2+3^3+.....+3^{2017}\)
\(3B=3^2+3^3+....+3^{2018}\)
\(3B-B=2B=3^{2018}-3\)
\(B=\frac{3^{2018}-3}{2}\)
Nhớ k cho mình nhé! Thank you!!!