Tớ nghĩ đề là :
\(\left(1+\dfrac{1}{2.4}\right)\left(1+\dfrac{1}{3.5}\right)\left(1+\dfrac{1}{4.6}\right)...\left(1+\dfrac{1}{99.101}\right)\)
\(=\dfrac{9}{2.4}.\dfrac{16}{3.5}.\dfrac{25}{4.6}....\dfrac{10000}{99.101}=\dfrac{3.3.4.4.5...100.100}{2.4.3.5.4....99.101}\)
\(=\dfrac{3.100}{2.101}=\dfrac{150}{101}\)
A=(1-1/2).(1-1/3). ... .(1-1/2011)
B=3/2.4/3.5/4.6/5. ... .1000/999
1) Tính giá trị biểu thức
A=\(\left(\frac{1}{2}+1\right)\left(\frac{1}{3}+1\right)\left(\frac{1}{4}+1\right)...\left(\frac{1}{99}+1\right)\)
2) Tính nhanh:
\(\frac{-17}{2.4}-\frac{17}{4.6}-\frac{17}{6.8}-...-\frac{17}{100.102}\)
A=1.3+2.4+3.5+...+98.100+99.101
Tính tổng A= 1/2.4 + 1/4.6+.... +1/48.50
Tính :
C = \(\left(1+\dfrac{1}{2.3}\right)\) \(\left(1+\dfrac{1}{2.4}\right)\) \(\left(1+\dfrac{1}{3.5}\right)\) .....\(\left(1+\dfrac{1}{2014.2016}\right)\)
tinh: \(\dfrac{1}{3.5}+\dfrac{1}{5.7}+\dfrac{1}{7.9}+...+\dfrac{1}{99.101}\)
Tính:
1. (1 - 1/2) (1 - 1/3) ... (1- 1 / 100)
2. 1 / 2.4 + 1 / 4.6 ... + 1 / 98.100
tính
\(A=\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+.....+\frac{1}{2018.2020}\)
1/(2.4) + 1/(4.6) + … + 1/[(2x – 2).2x] = 1/8 (x ∈ N, x ≥ 2)
giup vs
