Tính:
D=(1-1/1.2)+(1-1/2.3)+....+(1-1/2015.2016)
Tính -1/1.2+-1/2.3+-1/3.4+...+-1/2015.2016+1/2016=?
tính (1-1/1.2)+(1-1/2.3)+(1-1/3.4)+...+(1-1/2015.2016)
\(=\frac{0}{1.2}+\frac{0}{2.3}+\frac{0}{3.4}+...+\frac{0}{2015.2016}\)
\(=0+0+0+...+0=0\)
Tinh tong S =1/1.2+1/2.3+1/3.4+...+1/2014.2015+1/2015.2016
\(S=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+.......+\frac{1}{2015.2016}\)
\(S=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+.......+\frac{1}{2015}-\frac{1}{2016}\)
\(S=\frac{1}{1}-\frac{1}{2016}=\frac{2015}{2016}\)
S=1/1-1//2+1/2-1/3+1/3-1/4+.......=1/2014-1/2015
S=1/1-1/2015
S=2015/2015-1/2015
S=2014/2015
tính
D=(1-1/1.2)+(1-1/2.3)......+(1-1/2015.2016)
Tính:
D= 10/100 + 10/150 + 10/210 +...+ 10/1200
E= 1.2 + 2.3 + 3.4 +...+ 99.100
F= 1² + 2² + 3² +...+ 97² + 98²
\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{2015.2016}+\frac{1}{2016.2017}\)
\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+...+\frac{1}{2016\cdot2017}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2016}-\frac{1}{2017}\)
\(=1-\frac{1}{2017}=\frac{2016}{2017}\)
\(S=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+..........+\frac{1}{2015.2016}\)
S=2-1/1.2 . 3-2/2.3............2016-2015/2015.2016
=1/1 - 1/2 + 1/2 - 1/3+........+1/2015 - 1/2016
=1/1 - 1/2016
=2015/2016
A = \(\left(1-\frac{1}{1.2}\right)+\left(1-\frac{1}{2.3}\right)+...+\left(1-\frac{1}{2015.2016}\right)\)
TÍNH
\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+........+\frac{1}{2015.2016}\)