Tinh:

\(\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

Giup minh trinh bay cach cach giai voi nhe

Ko hieu vao phan"Doc them"

Tinh 

D=  \(\frac{\frac{1}{3}+\frac{1}{17}-\frac{1}{13}}{\frac{2}{3}+\frac{2}{17}-\frac{2}{13}}.\frac{\frac{3}{4}-\frac{3}{16}+\frac{3}{64}-\frac{3}{256}}{1-\frac{1}{4}+\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)

Trinh bay cach lam nhe

Ko hieu vao DOC THEM

Tinh:

\(B=\frac{\frac{1}{7}+\frac{1}{23}-\frac{1}{1009}}{\frac{1}{7}+\frac{1}{23}-\frac{1}{1009}+\frac{1}{7}.\frac{1}{23}.\frac{1}{1009}}\)

Trinh bay cach lam nua nhe

Co gi ko hieu thi vao phan doc them

Tinh :

A=\(\left(1+\frac{1}{1.3}\right)\left(1+\frac{1}{2.4}\right)\left(1+\frac{1}{3.5}\right)....\left(1+\frac{1}{2014.1016}\right)\)

Giup minh trinh bay ca cach lam nua nha!

Ai chua doc het de va ko hieu thi vao phan "Doc them" se ro

Thanks

Tinh :

A=\(\left(1+\frac{1}{1.3}\right)\left(1+\frac{1}{2.4}\right)\left(1+\frac{1}{3.5}\right)......\left(1+\frac{1}{2014.2016}\right)\)

Giup minh trinh bay ca cach lam nua nha!

Ai chua doc het de va ko hieu thi vao phan "Doc them" se ro

Thanks

Chung minh:

\(\frac{n\left(n+1\right)}{2}\) va 2n+1 nguyen to cung nha voi moi n thuoc N

helps me

Neu ai doc ko het thi vao phan doc them thi se hieu ro hon nhe

So sanh A va B biet: A=\(\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2010}\)                                                                                      va B=\(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+...+\frac{1}{17}\)

Trinh bay cach lam cho minh voi nhe

Ai ko hieu thi vao phan "Doc them"

Giup minh voi nhe!Please

tim x biet:

\(\frac{x-5}{1990}+\frac{x-15}{1980}+\frac{x-25}{1970}=\frac{x-1990}{5}+\frac{x-1980}{15}+\frac{x-1970}{25}\)

trinh bay cach giai ho minh nhe

co gi ko hieu thi vao cho"doc them"

   a)  Cho \(s=\frac{3}{10}+\frac{3}{11}+\frac{3}{12}+\frac{3}{13}+\frac{3}{14}\)

CMR 1<s<2, từ đó suy ra s ko phải stn

   b)  Cho \(s=\frac{1}{31}+\frac{1}{32}+\frac{1}{33}+....+\frac{1}{60}\)

CMR 3/5< s  < 4/5