\(B=\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+...+\dfrac{1}{2022.2023}\)
\(B=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+...+\dfrac{1}{2022}-\dfrac{1}{2023}\)
\(B=\dfrac{1}{2}-\dfrac{1}{2023}=\dfrac{2021}{4046}\)
Câu 10 (1,0 điểm)
Cho S = \(\dfrac{1}{2x3}+\dfrac{1}{4x5}+\dfrac{1}{6x7}+...+\dfrac{1}{2020x2021}+\dfrac{1}{2022x2023}\)
So sánh S với \(\dfrac{1011}{2023}\)
1313/1212 : x = 1/1x2+1/2x3+1/3x4+1/4x5+1/5
1/12+1/2x3+1/3x4+1/4x5
tính 1/2x3+1/3x4+1/4x5+...1/99x100
tính : 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6
Tính giá trị của 1/2x3+1/3x4+1/4x5+...+1/98+1/99xx100
tinh:
a,1/2x3 +1/3x4 + 1/4x5 +.....+1/99x100
1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+.....+1/11x12
Tính :
a) 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+.....+1
b)1/1x2x3+1/2x3x4+1/3x4x5+.....+1/98x99x100
