anh chị giúp em nhé
\(x = {{2.1.2+1} \over 1.2}+{{2.2.3+1} \over 2.3}+ {{2.3.4+1} \over 3.4}+{{2.4.5+1} \over 4.5}+...+{{2.9.10+1} \over 9.10}\)
(2.1.2 + 1/1.2) + (2.2.3 + 1/2.3) + (2.3.4 + 1/3.4) + (2.4.5 + 1/4.5)+...+(2.9.10 + 9/10) = ?
3. \(\frac{\left(1+2^2+3^2+...+2005^2\right).12}{2.3+4.6+6.9+...+4010.6015}\)
GIẢI CHI TIẾT NHA. LẸ NHA. THANKS
Tinh tong: S= 1/1.2 + 1/2.3+ 1/ 3.4 ..... + 1/9.10?
1/1.2+5/2.3+11/3.4+...+89/9.10
Tính
a 1/1.2+1/2.3+1/3.4+.......+1/9.10
10.(1/1.2+5/2.3+11/3.4+...+89/9.10)
\(\frac{1}{1.2}-\frac{1}{2.3}-\frac{1}{3.4}-.....-\frac{1}{9.10}\)
Tính:
10.(1/1.2+5/2.3+11/3.4+...+89/9.10)