Gọi 1/4 số a là 0,25 . Ta có :
a . 3 - a . 0,25 = 147,07
a . (3 - 0,25) = 147,07 ( 1 số nhân 1 hiệu )
a . 2,75 = 147,07
a = 147,07 : 2,75
a = 53,48
\(E=\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2000}}{\frac{1999}{1}+\frac{1998}{2}+\frac{1997}{3}+..+\frac{1}{1999}}\)
Tính
A=\(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+.....+\frac{1}{2000}}{\frac{1999}{1}+\frac{1998}{2}+\frac{1997}{3}+......+\frac{1}{1999}}\)
Ai nhanh và đúng mình tick cho
\(T\text{ính}:\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2000}}{\frac{1999}{1}+\frac{1998}{2}+\frac{1997}{3}+...+\frac{1}{1999}}\)
\(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{20}}{\frac{1999}{1}+\frac{1998}{2}+\frac{1997}{3}+...+\frac{1}{1999}}\)
Tìm x, biết:
\(\left(\frac{1999}{2}+\frac{1998}{3}+\frac{1997}{4}+.......+\frac{1}{2000}+4000\right)x=1+\frac{1}{2}+\frac{1}{3}\)\(\frac{1}{3}\)
TÍNH HỢP LÍ
a)\(\frac{\frac{4}{17}-\frac{4}{49}-\frac{4}{131}}{\frac{-3}{17}+\frac{3}{49}+\frac{3}{131}}\)
b)\(\frac{-1}{2}+\frac{3}{5}+\frac{-1}{9}+\frac{1}{27}+\frac{7}{18}+\frac{4}{35}+\frac{2}{7}\)
c)\(\frac{3.8.15....9999}{4.9.16.....10000}\)
d)\(\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2000}}{\frac{1999}{1}+\frac{1998}{2}+\frac{1997}{3}+...+\frac{1}{1999}}\)
A=\(\frac{\frac{2000}{1}+\frac{1999}{2}+...+\frac{1}{2000}+2000}{1+\frac{1999}{2}+\frac{1998}{3}+....+\frac{1}{2000}}\)
Các bạn giải dùm mình nha
Tìm x,y \(\in Z\):
|x-3|.|x+3|=16
Chứng minh:
\(\frac{1}{2^2}+\frac{1}{4^2}+\frac{1}{6^2}+...+\frac{1}{2016^2}< \frac{1}{2}\)
So sánh:
\(A=\frac{1999^{1999}+1}{1999^{2000}+1}\)và \(B=\frac{1999^{1998}+1}{1999^{1999}+1}\)
\(\frac{x+1}{2001}+\frac{x+2}{2000}=\frac{x+3}{1999}+\frac{x+4}{1998}\)
