a) S1 = 1+2^2+2^3+......+2^20
b) S2 =1+3^2+3^3+.......+3^15
c)S3 =6+5^2+5^3+........+5^10
d)S4= 1.2+2.3+3.4+......+99.100
e)S5 = 2.2+2.5+3.8+.....+50.149
Tính tổng :
Sn =1.2+2.5+3.8+.......+n(3n-1)
a)\(\frac{1}{24}+\frac{1}{60}+\frac{1}{120}+...+\frac{1}{2184}\)
b) 1+2+2^2 + 2^3 +...+ 2^100
c) 1! + 2.2! + 3.3! +...+ 10.10!
d) 1.2 + 2.5 + 3.8 + ... + 50.149
e) 1^2 + 2^2 + 3^2 +...+ 10^2
Các bạn làm cho mk nhoa!
tính tổng
\(A=\frac{1}{1.2}+\frac{2}{1.3}+\frac{3}{2.5}+\frac{5}{3.8}+\frac{8}{5.13}+\frac{13}{8.21}+...+\frac{987}{610.1597}\)
\(B=\frac{2^2}{1.3}+\frac{3^2}{2.4}+\frac{4^2}{3.5}+...+\frac{2017^2}{2016.2018}\)
\(C=\frac{5}{1.2.3}+\frac{8}{2.3.4}+\frac{11}{3.4.5}+...+\frac{6025}{2011.2012.2013}\)
TÍNH NHANH
A= 1/1.2+1/2.3+1/3.2+...+1/50.51
B= 3/2.3+3/3.8+3/8.11+...+3/47.50
tính hợp lí:
a 2.53.12+4.6.87-3.8.40
b C=4/5.7+4/7.9+...+4/59.61
c B=1.2+2.3+3.4+...+99.100
d E=1.2+3.4+5.6+...+99.100
F=1.4+2.5+3.6+....+97.100
Thực hiện phép tính:
a) \(\frac{\left(2^3.3^3\right)^2.5^5}{\left(2^2\right).\left(3^2.5^2\right)^2}\)
b) \(\frac{2^3.11-2^3.8}{6.\left(-1\right)^{2014}}\)
Tính:1.2+2.3+3.8+....+38.39+39.40
a) A=1+2+3+...+n (n thuộc N*)
b) A=1.2+2.3+3.4+...+99.100
c) A=1.4+2.5+3.6+...+99.102
d) A=1+3+6+10+...+4850+4950
e) A=4+12+24+40+...+19404+19800
f) A=49+64+81+...+169
Các bạn làm nhanh giúp mình với nha :))