tính:S=2^100-2^99+2^98+...+2^2-2
Cho:1^2+2^2+3^2+...+10^2=385.Tính:S=2^2+4^2+6^2+...+20^2
Cho 3 số a,b,c thỏa mãn:a.b.c=1. Tính:S= \(\frac{1}{1+a+ab}+\frac{1}{1+b+bc}+\frac{1}{1+c+ca}\)
So sanh A va B
A=-1/2011-3/11^2-5/11^3-7/11^4
B=-1/2011-7/11^2-5/11^3-3/11^4
1) Tính 2/3.5+2/5.7+2/7.9+2/9.11+2/11.13+2/13.15+2/1.2+2/2.3+2/3.4+2/4.5+...+2/9.10
2) Tìm x biết: (11/12+11/12.24+11/23.34+...+11/89.100)
Sanh A va B biet :
A = -2 /2011 - 3/ 112 -5/113 -7/114
B = -1/2011 -7/112 -5/113 -3/114
\( A=\frac{1+13+13^2+...+13^{13}}{1+13+13^2+...+13^{12}}\) và \(B=\frac{1+11+11^2+...+11^{13}}{1+11+11^2+...+11^{12}}\) chứng minh A > B
So sanh A va B biet
A = -2 /2011 -3/112 -5/113- 7/114
B = -1/2011 - 7/112 -5/113 - 3/114
tính nhanh
g))\(\frac{2^{10}.3^{11}+2^{10}.3^6}{2^{11}.3^{11}+2^{11}.3^6}\)
i) -3,15.(-7,2) + (-3,15).12,4 - 4,8 . 3,15 =
(3/4-13/11+7/5)-(3-1/2-35/11)+(11/4-2/5)