\(\frac{2}{3}cua\frac{9}{10}m\)
Cho \(M=\frac{1}{2}+\frac{2}{3}+\frac{3}{4}+\frac{4}{5}+\frac{5}{6}+\frac{6}{7}+\frac{7}{8}+\frac{8}{9}+\frac{9}{10}\)
So sánh M với 1
Ta có:
1 = \(\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+............+\frac{1}{10}\)(10 phân số \(\frac{1}{10}\))
Mà \(\frac{1}{2}>\frac{1}{10};\frac{2}{3}>\frac{1}{10};............;\frac{9}{10}>10\)
\(\Rightarrow M>1\)
Vậy M > 1
Ta có:
1/2=0,5
2/3>0,6
<=>1/2+2/3>1,1>1
<=>1/2+2/3+3/4+...+9/10>1
Vì 1 = \(\frac{1}{10}+\frac{1}{10}+...+\frac{1}{10}\)
\(\Rightarrow\)M > 1 vì \(\frac{1}{2}>\frac{1}{10};\frac{2}{3}>\frac{1}{10};...;\frac{9}{10}>\frac{1}{10}\)
\(\Rightarrow M>1\)
tinh nhanh
a) M= \(\frac{17}{5}.\frac{1}{2}.\frac{10}{17}.\frac{-1}{2^3}\)
b) N= \(\frac{1}{6}.\frac{5}{9}+\frac{5}{9}.\frac{2}{7}+\frac{1}{9}.\frac{5}{7}-\frac{5}{9}.\frac{3}{7}\)
17/5×1/2×10/17×-1/8
17/10×-10/136
-170/1360
-1/8
5/54+10/63+5/63+15/63
5/54+15/63+15/63
5/54+30/63
315/3402+1620/3402
1935/3402
\(\frac{1}{2}-\frac{1}{3}-\frac{2}{3}+\frac{1}{4}+\frac{2}{4}+\frac{3}{4}-\frac{1}{5}-\frac{2}{5}-\frac{3}{5}-\frac{4}{5}+...+\frac{1}{10}+\frac{2}{10}+\frac{3}{10}+...+\frac{9}{10}\)\(+\)\(\frac{9}{10}\)
Đề bài là gì bạn ơi có chỗ ...
chưa có đề bạn ơi! Y_Y
Hok tốt ^_^
Quy luật của dãy số này là gì bạn có thể nói rõ ra đc ko
Tinh nhanh
a) M = \(\frac{17}{5}.\frac{1}{2}.\frac{10}{17}.\frac{-1}{2^3}\)
b) N = \(\frac{1}{6}.\frac{5}{9}.\frac{5}{9}.\frac{2}{7}+\frac{1}{9}.\frac{5}{7}\)\(-\frac{5}{9}.\frac{3}{7}\)
Tính nhanh:
M=\(\frac{-7}{9}.\frac{15}{49}.\frac{9}{7}.15.\frac{14}{15}\)
N=\(\frac{5}{9}.\frac{4}{7}.\frac{10}{3}+\frac{15}{45}.\frac{3}{7}.\frac{1}{2}\)
\(M=\frac{\left(-7\right).15.9.15.14}{9.49.7.15}=\frac{-15.2}{7}=\frac{-30}{7}.\)
\(N=\frac{200}{189}+\frac{1}{14}=\)1.12962962963
\(M=\left(\frac{-7}{9}\cdot\frac{9}{7}\right)\cdot\left(\frac{15}{49}\cdot\frac{14}{15}\right)\cdot15\)
\(M=\left(-1\right)\cdot\frac{2}{7}\cdot15\)
\(M=\frac{-30}{7}\)
\(N=\frac{5}{9}\cdot\frac{4}{7}\cdot\frac{10}{3}+\frac{3}{9}\cdot\frac{3}{7}\cdot\frac{1}{2}\)
\(N=\frac{200\cdot2}{189\cdot2}+\frac{9\cdot3}{126\cdot3}\)
\(N=\frac{400}{378}+\frac{27}{378}\)
\(N=\frac{61}{51}\)
T i ck nha
Biết \(2-\frac{3}{4-\frac{5}{6-\frac{7}{8-\frac{9}{10}}}}=2-\frac{3}{4-\frac{5}{x}}\). Tìm x.
Không biết đề làm sao mình làm được đây
bài 13 tính nhanh
a\(-\frac{5}{9}+\frac{3}{5}-\frac{3}{9}+-\frac{2}{5}\)
b\(\frac{2}{17}-\frac{9}{15}-\frac{2}{17}+-\frac{2}{5}\)
c\(-\frac{5}{13}-\left(\frac{3}{5}+\frac{3}{13}-\frac{4}{10}\right)\)
d\(\left(\frac{1}{9}-\frac{9}{17}\right)+\frac{3}{6}-\left(\frac{12}{17}-\frac{1}{2}\right)+\frac{5}{9}\)
( câu a là âm \(\frac{5}{9}\) ; âm \(\frac{2}{5}\) ; câu b là âm \(\frac{2}{5}\) ; câu c là âm\(\frac{5}{13}\)
\(\frac{9}{10}+\frac{9}{10^2}+\frac{9}{10^3}+...+\frac{9}{10^{10}}\)
hay so sanh m voi 1
M=\(\frac{1}{2!}+\frac{2}{3!}++......+\frac{9}{10!}\)
\(M=\frac{1}{1.2}+\frac{2}{1.2.3}+.....+\frac{9}{1.2.3.....10}\)
\(M=\frac{2-1}{1.2}+\frac{3-1}{1.2.3}+....+\frac{10-1}{1.2......10}\)
\(M=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{6}+....+\frac{10}{1.2.....10}-\frac{1}{1.2.....10}\)
\(M=1-\frac{1}{1.2.3......10}\)
\(M=1-\frac{1}{3628800}\)
Vì \(1=1\)mà \(\frac{1}{3628800}< 1\)nên \(1-\frac{1}{3628800}< 1\)
Vậy \(M< 1\)