\(\dfrac{1}{1\times2}\) + \(\dfrac{1}{2\times3}\) + \(\dfrac{1}{3\times4}\)+...+\(\dfrac{1}{99\times100}\)
= \(\dfrac{1}{1}\) - \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) - \(\dfrac{1}{3}\) + \(\dfrac{1}{3}\) - \(\dfrac{1}{4}\) +...+ \(\dfrac{1}{99}\) - \(\dfrac{1}{100}\)
= \(\dfrac{1}{1}\) - \(\dfrac{1}{100}\)
= \(\dfrac{99}{100}\)
Tính:1/1x2 + 1/2x3 + 1/3x4 + ... + 1/98x99 + 1/99x100
Tính:1/(1x2)+1/(2x3)+1/(3x4)+1/(4x5)+...+1/(98x99)+1/(99x100)
1/2x3+ 1/3x4 + 1/4x5
các ac giúp e với ạ
e cảm ơn ac nhiều ạ
1/1x2+1/2x3+1/3x4+...+1/99x100=?
\(\dfrac{1}{1x2}\)+ \(\dfrac{1}{2x3}\) + \(\dfrac{1}{3x4}\) +...+ \(\dfrac{1}{98x99}\) + \(\dfrac{1}{99x100}\)
tính nhanh bài này
Tính nhanh :
A = 1/1x2 + 1/2x3 + 1/3x4 + 1/4x5 + ........1/98x99 + 1/99x100 .
1/1x2 + 1/2x3 + 1/3x4 + ... + 1/99x100
tinh nhanh
Tính nhanh
A=1/2+1/4+1/8+1/16+1/32+1/64+1/128
B=1/1x2+1/2x3+1/3x4+............1/99x100
\(\frac{1}{1x2}+\frac{1}{2x3}+\frac{1}{3x4}+.....+\frac{1}{99x100}\)
