B=1/3-1/4+1/4-1/5+...+1/95-1/96
B=1/3-1/96
B=31/96
Đúng 0
Bình luận (0)
Violympic toán 6
Các câu hỏi tương tự
\(\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+\dfrac{1}{5.6}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)
Chứng minh rằng:
\(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)
tính nhanh
A=\(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+\dfrac{1}{5.6}\)
B=\(\dfrac{1}{10}+\dfrac{1}{15}+\dfrac{1}{21}+...+\dfrac{1}{120}\)
các bn giúp mk nha
\(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) + \(\dfrac{1}{4.5}\) + \(\dfrac{1}{5.6}\) + \(\dfrac{1}{6.7}\) + \(\dfrac{1}{7.8}\)
Giup với mai KT ròi.
Thanks nha.
1. tính
a) A=\(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}\)
b) B=\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\)
c) C=\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{99.101}\)
d) D=\(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{92.98}\)
Tính B:C, biết: B=1/51+1/52+1/53+............+1/100
C= 1/1.2+1/3.4+1/5.6+..............+1/99.100
CMR:1/2+1/3.4+1/5.6+...+1/2015.2106=1/1009+1/1010+...+1/2016
a)6/1.4+6/4.7+6/7.10+....+6/97.100
b 4/1.3+16/3.5+36/5.7+.....+9604/97.99
c (1/1.2+1/3.4+1/5.6+...........+1/19.20)-(1/11+1/12+.....+1/20)
Tính : S=1.2+3.4+5.6+...+(2n-1).2n (n thuộc N*)