\(B=3+3^3+3^5+3^7+...+3^{2015}+3^{2017}\)
\(9B=3^3+3^5+3^7+3^9+...+3^{2017}+3^{2019}\)
\(9B-B=\left(3^3+3^5+3^7+3^9+...+3^{2017}+3^{2019}\right)-\left(3+3^3+3^5+3^7+...+3^{2015}+3^{2017}\right)\)
\(8B=3^{2019}-3\)
\(B=\frac{3^{2019}-3}{8}\)
\(B=3+3^3+3^5+3^7+...+3^{2015}+3^{2017}\)
\(9B=3^3+3^5+3^7+3^9+...+3^{2017}+3^{2019}\)
\(9B-B=\left(3^3+3^5+3^7+3^9+...+3^{2017}+3^{2019}\right)-\left(3+3^3+3^5+3^7+...+3^{2015}+3^{2017}\right)\)
\(8B=3^{2019}-3\)
\(B=\frac{3^{2019}-3}{8}\)
tính tổng:
a) 2+4+6+...+2016+2018
b) 1+3+5+7+...+2015+2017
Tính :
A = 1 + (-2) + 3 + (-4) + ... + 2014 + (-2015)
B = 1 + (-3) + 5 + (-7) + ... + 2015 + (-2017)
C = 1 + (-2) + (-3) + 4 + 5 + (-6) + (-7) + 8 + ... + (-1998) + (-1999) + (-2000) + 2001
a) Tính Nhanh: 1+2-3-4+5+6-7-8+9+.............+1003+1004-1005-1006+1007.
b)Tính Tổng: 1 - 2 - 3 + 4 + 5 - 6 - 7 + 8+ 9 -......... + 2013 - 2014 -2015 + 2016 + 2017.
giải gấp cho mik nha. Mik tích cho
tính tổng sau
A= 5+10+15+...+2015
B=3+5+7+9+....+2017
Tính các tổng sau:
a) S= 1+ 4 + 7 + ..........+ 2017
b) T= 1-2+3-4+..........+2015-2016+2017
Hãy tính tổng:
a) A=1+3+3 mũ 2+3 mũ 3+...+3 mũ 2018
b)B=5+5 mũ 2+...+5 mũ 2017
A=3/1*3+3/3*5+3/5*7+......+3/2015*2017
Tính các tổng sau
S = 1+3+5+…+2015+2017
A. S = 1018080
B. S = 1018081
C. S = 1018181
D. S = 1017072
Tính
A=1*2+2*3+3*4+4*5+...+99*100
B=7*8*9+8*9*10+9*10*11+...+2015*2016*2017
C=1+3+3^2+3^3+3^4+3^5+...+3^49+3^50