bài 1:tìm X
phần a, 1/1x2 + 1/ 2x 3 + 1/ 3 x4 + ....+ 1/ X x( X +1)= 499 / 500
phần b,1/1x3 + 1/3x5 + 1/ 5 x 7+ ....+ 1/X x ( X + 2 )= 20 /41
a)1/1x3+1/3x5+1/5x7+...+1/Xx(x+3)=99/200
b)1/1x3+1/3x5+1/5x7+...+1/Xx(x+2)
Tìm x:
\(\left(x+\frac{1}{1x3}\right)+\left(x+\frac{1}{3x5}\right)+......+\left(x+\frac{1}{23x25}\right)=11.x+\left(\frac{1}{3}+\frac{1}{9}+\frac{1}{81}+\frac{1}{243}\right)\)
Help me please! Thanks a lot!
1/1x3 + 1/3x5 + 1/5x7 + .....+ 1/ (2n+1)x(2n+3) =n+1/2n+3
Tìm n với điều kiện n khác 0
a,1/1x3+1/3x5+1/5x7+1/7x9+1/X=1;b,2/3-1/3x(X-2)=1/4
(1+1/1x3)x(1+1/2x4)x(1+1/3x5)x...x(1+1/99x101)
\(\frac{1}{1x3}+\frac{1}{3x5}+\frac{1}{5x7}+......+\frac{1}{Xx\left(X+2\right)}=\frac{8}{17}\)
Tìm x, biết x là số lẻ
Tìm chữ số tận cùng của tích sau: 1 x 3 x5 x 7 x 9 x.....x2009 x 2011.
(1+1/1x3)x(1+1/2x4)x(1+1/3x5)x(1+1/4x6)x(1+1/5x7)