A = 1+ 1/ 2.2 + 1 / 3.3 +1/ 4.4 + ....+1/99.99 + 1/ 100. 100
CMR: 1/2.2 +1/3.3+1/4.4+....+1/100.100<1
Mik cần gấp
Chung minh M<3/4
Cho M=1/2.2/3.5/6......99/100 và N=2/3.3/4.5/6....100/101
M . N = ?
2/5<1/2.2+1/3.3+1/4.4+...+1/9.9<8/9
cho a=1/2.3/4.5/6. ... .99/100;b=2/3.4/5. ... .100/101;c=1/2.2/3.3/4. ... 98/99 a, so sánh a, b,c b,chứng minh a.c<a^2<1/100 c,chứng minh 1/15<a<1/10
1/2.2+1/3.3+1/4.4+....+1/100.100<1
tính : A= 1/2.2+1/3.3+1/4.4+...+1/9.9
B=2/3.3+2/5.5+2/7.7+...+2/2007.2007
C=1/4.4+1/6.6+1/8.8+...+1/2006.2006
A=1+2.2!+3.3!+4.4!+...+100.100!