\(\dfrac{1}{3}\)+\(\dfrac{1}{15}\)+\(\dfrac{1}{35}\)+...+\(\dfrac{1}{97,99}\)
Tính tổng trên:
Những câu hỏi liên quan
tính nhanh: m= \(\dfrac{1}{3,5}\)+\(\dfrac{1}{5,7}\)+\(\dfrac{1}{7,9}\)+\(\dfrac{1}{9,11}\)+...+\(\dfrac{1}{97,99}\)
=1/2(2/3*5+2/5*7+...+2/97*99)
=1/2(1/3-1/5+1/5-1/7+...+1/97-1/99)
=1/2*32/99
=16/99
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Tính nhanh
a, S dfrac{1}{3} + dfrac{1}{15} + dfrac{1}{35} + dfrac{1}{63} + dfrac{1}{99} + dfrac{1}{143}
b, A dfrac{1}{3} + dfrac{1}{6} + dfrac{1}{10} + dfrac{1}{15} + dfrac{1}{21} + dfrac{1}{28}
c, H dfrac{4047991-2010x2009}{4050000-2011x2009}
d, T dfrac{2009x20010+2000}{2011x2010-2020}
e, P dfrac{7589-80,5x69,3}{7485,05-79x69,3}
f, B 5,1 x 42,2 + 1,7 x 448 x 3 - 0,15 x 700
Giúp mình với
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Tính nhanh
a, S= \(\dfrac{1}{3}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{35}\) + \(\dfrac{1}{63}\) + \(\dfrac{1}{99}\) + \(\dfrac{1}{143}\)
b, A = \(\dfrac{1}{3}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{10}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{21}\) + \(\dfrac{1}{28}\)
c, H =\(\dfrac{4047991-2010x2009}{4050000-2011x2009}\)
d, T = \(\dfrac{2009x20010+2000}{2011x2010-2020}\)
e, P = \(\dfrac{7589-80,5x69,3}{7485,05-79x69,3}\)
f, B = 5,1 x 42,2 + 1,7 x 448 x 3 - 0,15 x 700
Giúp mình với
a=78/35
b=22/12
c=1/1
d=40202090/4040090
e=1,24025667172...
f=871,82
ko biết đúng ko [0_0'] hihi
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Tính tổng sau đây:
a,\(\dfrac{-3}{12}\)+\(\dfrac{1}{-4}\) b,\(\dfrac{5}{12}+\dfrac{-3}{28}\) c,\(\dfrac{-7}{15}+\dfrac{3}{35}\) d,\(\dfrac{-5}{7}+\dfrac{-3}{4}\)
Giúp mk với.
a. \(\dfrac{-3}{12}+\dfrac{1}{-4}=\dfrac{-3}{12}+\dfrac{-3}{12}=\dfrac{-3-3}{12}=\dfrac{-6}{12}=\dfrac{-1}{2}\)
b. \(\dfrac{5}{12}+\dfrac{-3}{28}=\dfrac{35}{84}+\dfrac{-9}{84}=\dfrac{35+\left(-9\right)}{84}=\dfrac{26}{84}=\dfrac{13}{42}\)
c. \(\dfrac{-7}{15}+\dfrac{3}{35}=\dfrac{-49}{105}+\dfrac{9}{105}=\dfrac{-49+9}{105}=\dfrac{-40}{105}=\dfrac{-8}{21}\)
d. \(\dfrac{-5}{7}+\dfrac{-3}{4}=\dfrac{-20}{28}+\dfrac{-21}{28}=\dfrac{-20+\left(-21\right)}{28}=\dfrac{-41}{28}\)
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10 tháng 3 2022 lúc 9:18
Tính hợp lí :A dfrac{-2}{9} + dfrac{-3}{4} + dfrac{3}{5} + dfrac{1}{15} + dfrac{1}{57} + dfrac{1}{3} + dfrac{-1}{36}B dfrac{1}{2} + dfrac{-1}{5} + dfrac{-5}{7} + dfrac{1}{6} + dfrac{-3}{35} + dfrac{1}{3} + dfrac{1}{41}C dfrac{-1}{2} + dfrac{3}{5} + dfrac{-1}{9} + dfrac{1}{127} + dfrac{-7}{18} + dfrac{4}{35} + dfrac{2}{7}
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Tính hợp lí :
A = \(\dfrac{-2}{9}\) + \(\dfrac{-3}{4}\) + \(\dfrac{3}{5}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{57}\) + \(\dfrac{1}{3}\) + \(\dfrac{-1}{36}\)
B = \(\dfrac{1}{2}\) + \(\dfrac{-1}{5}\) + \(\dfrac{-5}{7}\) + \(\dfrac{1}{6}\) + \(\dfrac{-3}{35}\) + \(\dfrac{1}{3}\) + \(\dfrac{1}{41}\)
C = \(\dfrac{-1}{2}\) + \(\dfrac{3}{5}\) + \(\dfrac{-1}{9}\) + \(\dfrac{1}{127}\) + \(\dfrac{-7}{18}\) + \(\dfrac{4}{35}\) + \(\dfrac{2}{7}\)
8 tháng 2 2022 lúc 9:29
Tính nhanhA dfrac{1}{2} + ^{dfrac{1}{3}} + dfrac{1}{6} + dfrac{1}{12} + dfrac{1}{15} + dfrac{1}{20} + dfrac{1}{25} + dfrac{1}{30} + dfrac{1}{35} + dfrac{1}{42} + dfrac{1}{56} + dfrac{1}{63}Mình đang cần gấp , mong mn giúp mình với ạ
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Tính nhanh
A = \(\dfrac{1}{2}\) + \(^{\dfrac{1}{3}}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{12}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{20}\) + \(\dfrac{1}{25}\) + \(\dfrac{1}{30}\) + \(\dfrac{1}{35}\) + \(\dfrac{1}{42}\) + \(\dfrac{1}{56}\) + \(\dfrac{1}{63}\)
Mình đang cần gấp , mong mn giúp mình với ạ
quy đòng r tính nha ra \(\dfrac{199}{33}\)
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20 tháng 4 2023 lúc 11:59
tính tổng \(M=1+\dfrac{1}{5}+\dfrac{3}{35}+...+\dfrac{3}{9603}+\dfrac{3}{9999}\)
\(M=\dfrac{6}{5}+\dfrac{3}{2}\left(\dfrac{2}{35}+\dfrac{2}{63}+...+\dfrac{2}{9603}+\dfrac{2}{9999}\right)\)
\(=\dfrac{6}{5}+\dfrac{3}{2}\left(\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+...+\dfrac{1}{97}-\dfrac{1}{99}+\dfrac{1}{99}-\dfrac{1}{101}\right)\)
\(=\dfrac{6}{5}+\dfrac{3}{2}\cdot\dfrac{96}{505}=\dfrac{150}{101}\)
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Tính bằng cách thuận tiện nhất
1\(\dfrac{1}{3}\) x 1\(\dfrac{1}{8}\) x \(1\dfrac{1}{15}\) x \(1\dfrac{1}{24}\) x \(1\dfrac{1}{35}=\)
\(=\dfrac{4}{3}\cdot\dfrac{9}{8}\cdot\dfrac{16}{15}\cdot\dfrac{25}{24}\cdot\dfrac{36}{35}=\dfrac{12}{7}\)
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= 4/3*9/8*16/15*25/24*36/35
=2*2/1*3 * 3*3/2*4 *4*4/3*5 *5*5/4*6 * 6*6/5*7
= (2*3*4*5*6 / 1*2*3*4*5) * ( 2*3*4*5*6 / 3*4*5*6*7)
=6/1* 2/7
= 12/7
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Tính nhanh:
a, \(\dfrac{8}{9}-\dfrac{1}{72}-\dfrac{1}{56}-\dfrac{1}{42}-\dfrac{1}{30}-\dfrac{1}{20}-\dfrac{1}{12}-\dfrac{1}{6}-\dfrac{1}{2}\)
b, \(\left(-\dfrac{1}{4}+\dfrac{7}{35}-\dfrac{5}{3}\right)-\left(-\dfrac{15}{12}+\dfrac{6}{11}-\dfrac{48}{49}\right)\)
a: Ta có: \(\dfrac{8}{9}-\left(\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+...+\dfrac{1}{72}\right)\)
\(=\dfrac{8}{9}-\left(1-\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{3}-...+\dfrac{1}{8}-\dfrac{1}{9}\right)\)
=0
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Cíuuu
Bài 1: Tính nhanh
1) B= \(\dfrac{1}{15}+\dfrac{1}{35}+\dfrac{1}{63}+\dfrac{1}{99}+\dfrac{1}{143}\)
2) C= \(\dfrac{1}{2}+\dfrac{1}{14}+\dfrac{1}{35}+\dfrac{1}{65}+\dfrac{1}{104}+\dfrac{1}{152}\)
Bài 2: Chứng minh
\(\dfrac{1}{101}+\dfrac{1}{102}+\dfrac{1}{103}+\dfrac{1}{299}+\dfrac{1}{300}>\dfrac{2}{3}\)