Violympic toán 6
Các câu hỏi tương tự
Tính
\(B=\dfrac{1}{4}+\dfrac{1}{12}+\dfrac{1}{36}+\dfrac{1}{108}+\dfrac{1}{324}+\dfrac{1}{972}\)
Tính nhanh :
\(C=\dfrac{1}{3}+\dfrac{-3}{4}+\dfrac{3}{5}+\dfrac{1}{57}+\dfrac{-1}{36}+\dfrac{1}{15}+\dfrac{-2}{9}\)
\(D=\dfrac{1}{2}+\dfrac{-1}{5}+\dfrac{-5}{7}+\dfrac{1}{6}+\dfrac{-3}{35}+\dfrac{1}{3}+\dfrac{1}{41}\)
\(E=\dfrac{-1}{2}+\dfrac{3}{5}+\dfrac{-1}{9}+\dfrac{1}{127}+\dfrac{-7}{18}+\dfrac{4}{35}+\dfrac{2}{7}\)
4 tháng 2 2021 lúc 12:31
a) Tính A ( 1 - dfrac{1}{2} )( 1 - dfrac{1}{3} ) (1-dfrac{1}{4} ) ....(1-dfrac{1}{2014} ) (1-dfrac{1}{2015} ) (1-dfrac{1}{2016} )b)Tìm x biết dfrac{x-2}{12} + dfrac{x-2}{20} + dfrac{x-2}{30}+ dfrac{x-2}{42} + dfrac{x-2}{56} +dfrac{x-2}{72} dfrac{16}{9}
Đọc tiếp
a) Tính A = ( 1 - \(\dfrac{1}{2}\) )( 1 - \(\dfrac{1}{3}\) ) (1-\(\dfrac{1}{4}\) ) ....(1-\(\dfrac{1}{2014}\) ) (1-\(\dfrac{1}{2015}\) ) (1-\(\dfrac{1}{2016}\) )
b)Tìm x biết \(\dfrac{x-2}{12}\) + \(\dfrac{x-2}{20}\) + \(\dfrac{x-2}{30}\)+ \(\dfrac{x-2}{42}\) + \(\dfrac{x-2}{56}\) +\(\dfrac{x-2}{72}\) = \(\dfrac{16}{9}\)
Tính nhanh:
a) A 1 + dfrac{1}{5}+dfrac{1}{25}+dfrac{1}{125}+dfrac{1}{625}+...+dfrac{1}{78125}
b) B dfrac{1}{3}+dfrac{1}{12}+dfrac{1}{48}+dfrac{1}{192}+dfrac{1}{768}+...+dfrac{1}{36864}
c) M dfrac{1}{3}+dfrac{1}{6}+dfrac{1}{12}+dfrac{1}{20}+dfrac{1}{30}+...+dfrac{1}{9900}
d) P dfrac{1}{1+2}+dfrac{1}{1+2+3}+dfrac{1}{1+2+3+4}+...+dfrac{1}{1+2+3+4+...+2018}
Đọc tiếp
Tính nhanh:
a) A= 1 + \(\dfrac{1}{5}+\dfrac{1}{25}+\dfrac{1}{125}+\dfrac{1}{625}+...+\dfrac{1}{78125}\)
b) B= \(\dfrac{1}{3}+\dfrac{1}{12}+\dfrac{1}{48}+\dfrac{1}{192}+\dfrac{1}{768}+...+\dfrac{1}{36864}\)
c) M= \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+...+\dfrac{1}{9900}\)
d) P= \(\dfrac{1}{1+2}+\dfrac{1}{1+2+3}+\dfrac{1}{1+2+3+4}+...+\dfrac{1}{1+2+3+4+...+2018}\)
a/ Rút gọn 2 biểu thức sau: \(E=\dfrac{\dfrac{1}{99}+\dfrac{2}{98}+\dfrac{3}{97}+...+\dfrac{99}{1}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{100}}\)và \(F=\dfrac{94-\dfrac{1}{7}-\dfrac{2}{8}-\dfrac{3}{9}-...-\dfrac{94}{100}}{\dfrac{1}{35}+\dfrac{1}{40}+\dfrac{1}{45}+...+\dfrac{1}{500}}\)
b/ Tính E - 2F
Tính :
a, dfrac{3cdot13-13cdot18}{15cdot40-80};
b, dfrac{18cdot34+left(-18right)cdot124}{-36cdot17+9cdotleft(-52right)};
c, dfrac{dfrac{3}{41}-dfrac{12}{47}+dfrac{27}{53}}{dfrac{4}{41}-dfrac{16}{47}+dfrac{36}{53}}+dfrac{-0,25cdotdfrac{-2}{3}-0,75:left(dfrac{-1}{2}+dfrac{2}{3}right)}{left|-1dfrac{1}{2}right|cdotleft(dfrac{-2}{3}-75%:dfrac{3}{-2}right)}.
Đọc tiếp
Tính :
a, \(\dfrac{3\cdot13-13\cdot18}{15\cdot40-80}\);
b, \(\dfrac{18\cdot34+\left(-18\right)\cdot124}{-36\cdot17+9\cdot\left(-52\right)}\);
c, \(\dfrac{\dfrac{3}{41}-\dfrac{12}{47}+\dfrac{27}{53}}{\dfrac{4}{41}-\dfrac{16}{47}+\dfrac{36}{53}}+\dfrac{-0,25\cdot\dfrac{-2}{3}-0,75:\left(\dfrac{-1}{2}+\dfrac{2}{3}\right)}{\left|-1\dfrac{1}{2}\right|\cdot\left(\dfrac{-2}{3}-75\%:\dfrac{3}{-2}\right)}\).
Bài 1: Tính tổng 100 số hạng đầu tiên của các dãy sau:
a)dfrac{1}{2};dfrac{1}{6};dfrac{1}{12};dfrac{1}{20};dfrac{1}{30};...
b)dfrac{1}{6};dfrac{1}{66};dfrac{1}{176};dfrac{1}{336};...
Bài 2: Tính:
a)Adfrac{1+dfrac{1}{3}+dfrac{1}{5}+...+dfrac{1}{97}+dfrac{1}{99}}{dfrac{1}{1.99}+dfrac{1}{3.97}+dfrac{1}{5.95}+...+dfrac{1}{97.3}+dfrac{1}{99.1}}
b)Bdfrac{dfrac{1}{2}+dfrac{1}{3}+dfrac{1}{4}+...+dfrac{1}{100}}{dfrac{99}{1}+dfrac{98}{2}+dfrac{97}{3}+...+dfrac{1}{99}}
Đọc tiếp
Bài 1: Tính tổng 100 số hạng đầu tiên của các dãy sau:
a)\(\dfrac{1}{2};\dfrac{1}{6};\dfrac{1}{12};\dfrac{1}{20};\dfrac{1}{30};...\)
b)\(\dfrac{1}{6};\dfrac{1}{66};\dfrac{1}{176};\dfrac{1}{336};...\)
Bài 2: Tính:
a)A=\(\dfrac{1+\dfrac{1}{3}+\dfrac{1}{5}+...+\dfrac{1}{97}+\dfrac{1}{99}}{\dfrac{1}{1.99}+\dfrac{1}{3.97}+\dfrac{1}{5.95}+...+\dfrac{1}{97.3}+\dfrac{1}{99.1}}\)
b)B=\(\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{100}}{\dfrac{99}{1}+\dfrac{98}{2}+\dfrac{97}{3}+...+\dfrac{1}{99}}\)
Cho A dfrac{1}{2014}+dfrac{2}{2013}+dfrac{3}{2012}+...+dfrac{2013}{2}+2014 B dfrac{1}{2}+dfrac{1}{3}+dfrac{1}{4}+...+dfrac{1}{2015} Tính giá trị dfrac{A}{B}
Đọc tiếp
Cho A = \(\dfrac{1}{2014}\)+\(\dfrac{2}{2013}\)+\(\dfrac{3}{2012}\)+...+\(\dfrac{2013}{2}\)+2014
B = \(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)+\(\dfrac{1}{4}\)+...+\(\dfrac{1}{2015}\)
Tính giá trị \(\dfrac{A}{B}\)
Chứng mình rằng :
a) \(\dfrac{1}{4}+\dfrac{1}{16}+\dfrac{1}{36}+\dfrac{1}{64}+\dfrac{1}{100}+\dfrac{1}{144}+\dfrac{1}{196}< \)\(\dfrac{1}{2}\)
b)\(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{63}>2\)
Giup mk nha ! Đang cần gấp lắm rùi !