1:cho A=\(\frac{1}{7}\)+\(\frac{1}{13}\)+\(\frac{1}{25}\)+\(\frac{1}{49}\)+\(\frac{1}{97}\)
hay so sanh tong A voi \(\frac{1}{3}\)
giup minh nha.
minh cho 3 tich.
1:cho A=\(\frac{1}{7}\) +\(\frac{1}{13}\) +\(\frac{1.}{25}\) +\(\frac{1}{49}\) +\(\frac{1}{97}\)
hay so sanh tong A voi 13
giup minh nha.
minh cho 3 tich.
Cho A=1/7+1/13+1/25+1/49+1/97.
hay so sanh tong A voi 1/3
So sánh tổng A với \(\frac{1}{3}\):
A =\(\frac{1}{7}+\frac{1}{13}+\frac{1}{25}+\frac{1}{49}+\frac{1}{97}\)
\(\frac{1}{7}+\frac{1}{13}+\frac{1}{25}+\frac{1}{49}+\frac{1}{97}=A\).so sánh A và \(\frac{1}{3}\)
Điền dấu thích hợp vào chỗ chấm :
\(\frac{1}{7}+\frac{1}{13}+\frac{1}{25}+\frac{1}{49}+\frac{1}{97}.....\frac{1}{3}\)
Giup mk tich cho
\(\frac{1}{2.2}\)+\(\frac{1}{3.3}\)+...........+\(\frac{1}{100.100}\)so sanh voi 1
Đặt \(A=\frac{1}{2.2}+\frac{1}{3.3}+.....+\frac{1}{100.100}\)
\(\Rightarrow A< \frac{1}{1.2}+\frac{1}{2.3}+.....+\frac{1}{99.100}\)
\(\Rightarrow A< 1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+....+\frac{1}{99}-\frac{1}{100}\)
\(\Rightarrow A< 1-\frac{1}{100}\)
\(\Rightarrow A< \frac{99}{100}\)
Mà \(\frac{99}{100}< 1\Rightarrow A< \frac{99}{100}< 1\)
\(\Rightarrow A< 1\)
So sánh \(A\)với\(13\),biết rằng:
\(A=\frac{13}{15}+\frac{7}{5}+\frac{3}{4}+\frac{1}{5}+\frac{1}{7}+\frac{19}{20}+\frac{5}{4}+\frac{1}{3}+\frac{1}{6}+\frac{1}{13}+\frac{17}{23}+\frac{9}{8}+\frac{2}{5}+\frac{1}{7}+\frac{1}{25}+\frac{3}{2}+\frac{1}{8}+\frac{1}{19}+\frac{1}{9}+\frac{1}{97}\)
a,\(\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{13}}\)
b,\(\frac{5}{9}:\left(\frac{1}{3}+\frac{1}{4}\right)+\frac{5}{9}:\left(\frac{1}{9}+\frac{2}{3}\right)\)
giup minh voi!!!!
\(a,\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{13}}\)
\(=\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{13}}\)
\(=\frac{3\left[\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right]}{11\left[\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right]}=\frac{3}{11}\)
Câu b tương tự
#)Giải :
b)\(\frac{5}{9}:\left(\frac{1}{3}+\frac{1}{4}\right)+\frac{5}{9}:\left(\frac{1}{9}+\frac{2}{3}\right)\)
\(=\frac{5}{9}:\frac{1}{3}+\frac{5}{9}:\frac{1}{4}+\frac{5}{9}:\frac{1}{9}+\frac{5}{9}:\frac{2}{3}\)
\(=\frac{5}{9}:\left(\frac{1}{3}+\frac{1}{4}+\frac{1}{9}+\frac{2}{3}\right)\)
\(=\frac{5}{9}:\frac{49}{36}\)
\(=\frac{20}{49}\)
Hãy so sánh \(A\) với \(\frac{31}{6}\)biết rằng:\(A=\frac{1}{7}+\frac{1}{4}+\frac{2005}{2006}+\frac{1}{13}+\frac{1}{9}+\frac{2006}{2007}+\frac{1}{25}+\frac{1}{16}+\frac{2007}{2008}+\frac{1}{49}+\frac{1}{25}+\frac{2008}{2005}+\frac{1}{97}+\frac{1}{36}\).
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