1/6+1/10+1/15+.....+1/1830+1/1891
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(1/6 + 1/10 + 1/15) : (1/6 + 1/10 - 1/15 )
= (5/30 + 3/30 + 2/30) : (5/30 + 3/30 - 2/30)
= 7/30: 1/5
= 7/30.5 = 7/6.
a: \(\left(\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}\right):\left(\dfrac{1}{6}+\dfrac{1}{10}-\dfrac{1}{15}\right)\)
\(=\dfrac{5+3+2}{30}:\dfrac{5+3-2}{30}\)
\(=\dfrac{10}{30}\cdot\dfrac{30}{6}\)
\(=\dfrac{10}{6}=\dfrac{5}{3}\)
b: \(\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{1}{5}\right):\left(\dfrac{1}{4}-\dfrac{1}{6}\right)\)
\(=\dfrac{30-20+15-12}{60}:\dfrac{3-2}{12}\)
\(=\dfrac{13}{60}\cdot\dfrac{12}{1}=\dfrac{13}{5}\)
\(\frac{\frac{1}{6}+\frac{1}{10}+\frac{1}{15}}{\frac{1}{6}+\frac{1}{10}-\frac{1}{15}}=\frac{\frac{5+3+2}{30}}{\frac{5+3-2}{30}}=\frac{\frac{1}{3}}{\frac{1}{5}}=1\frac{2}{3}\)
\(\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{1}{4}-\frac{1}{6}}=\frac{\frac{30-20+15-12}{60}}{\frac{3-2}{12}}=\frac{\frac{13}{60}}{\frac{1}{12}}=2\frac{3}{5}\)
tíc nha mn, mình đang bị âm điểm
a (1/6 + 1/10 + 1/15) : (1/6 + 1/10 - 1/15)
= ( 5/30 + 3/30 + 2/30) : (5/30 + 3/30 - 2/30)
= 1/3 : 1/6 = 1/3 x 6/1 = 6/3 = 2
b (1/2 - 1/3 + 1/4 - 1/5) : (1/4 - 1/5)
= (1/2 - 1/3 + 1/4 - 1/5) : (1/4 - 1/5)
= 1/2 - 1/3 = 1/6
=(5/30+3/30+2/30) : (5/30+3/30-2/30)
=10/30 : 5/30
=10/30 x 30/5
=2
!!! Hok tốt!!!
\(\left(\frac{1}{6}+\frac{1}{10}+\frac{1}{15}\right):\left(\frac{1}{6}+\frac{1}{10}-\frac{1}{15}\right)\)
=\(\frac{10}{30}:\frac{6}{30}\)
\(=\frac{5}{3}\)
\(\dfrac{\left(\dfrac{5}{30}+\dfrac{3}{30}+\dfrac{2}{30}\right):\left(\dfrac{5}{30}+\dfrac{3}{30}-\dfrac{2}{30}\right)}{\left(\dfrac{30}{60}-\dfrac{20}{60}+\dfrac{15}{60}-\dfrac{12}{60}\right):\left(\dfrac{3}{12}-\dfrac{2}{12}\right)}=\dfrac{\dfrac{1}{3}:\dfrac{1}{5}}{\dfrac{13}{60}:\dfrac{1}{12}}=\dfrac{\dfrac{1}{3}\times5}{\dfrac{13}{60}\times12}=\dfrac{\dfrac{5}{3}}{\dfrac{13}{5}}=\dfrac{25}{39}\)
=2x(1/12+1/20+1/30+...+1/3660+1/3782)
=2x(1/(3x4)+1/(4x5)+1/(5x6)+...+1/(60x61)+1/(61x62)
=2x(1/3-1/4+1/4-1/5+1/5-1/6+...+1/60-1/61+1/61-1/62)
=2x(1/3-1/62)=2x59/186=59/93