Thực hiện tính :
M= 1+\(\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}.\left(1+2+3\right)+\dfrac{1}{4}\left(1+2+3+4\right)+....+\dfrac{1}{16}\left(1+....16\right)\)
(Giải thích rõ giùm mk vs nhá - thanks)
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Thực hiện phép tính:1, left(dfrac{-1}{2}right)^2.left|+8right|-left(-dfrac{1}{2}right)^3:left|-dfrac{1}{16}right|2, left|-0,25right|-left(-dfrac{3}{2}right)^2:dfrac{1}{4}+dfrac{3}{4}.2017^03, left|dfrac{2}{3}-dfrac{5}{6}right|.left(3,6:2dfrac{2}{5}right)^34, left|left(-0,5right)^2+dfrac{7}{2}right|.10-left(dfrac{29}{30}-dfrac{7}{15}right):left(-dfrac{2017}{2018}right)^05, dfrac{8}{3}+left(3-dfrac{1}{2}right)^2-left|dfrac{-7}{3}right|
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Thực hiện phép tính:
1, \(\left(\dfrac{-1}{2}\right)^2.\left|+8\right|-\left(-\dfrac{1}{2}\right)^3:\left|-\dfrac{1}{16}\right|\)
2, \(\left|-0,25\right|-\left(-\dfrac{3}{2}\right)^2:\dfrac{1}{4}+\dfrac{3}{4}.2017^0\)
3, \(\left|\dfrac{2}{3}-\dfrac{5}{6}\right|.\left(3,6:2\dfrac{2}{5}\right)^3\)
4, \(\left|\left(-0,5\right)^2+\dfrac{7}{2}\right|.10-\left(\dfrac{29}{30}-\dfrac{7}{15}\right):\left(-\dfrac{2017}{2018}\right)^0\)
5, \(\dfrac{8}{3}+\left(3-\dfrac{1}{2}\right)^2-\left|\dfrac{-7}{3}\right|\)
`1//([-1]/2)^2 . |+8|-(-1/2)^3:|-1/16|=1/4 .8+1/8 .16=2+2=4`
`2//|-0,25|-(-3/2)^2:1/4+3/4 .2017^0=0,25-2,25.4+0,75.1=0,25-9+0,75=-8,75+0,75-8`
`3//|2/3-5/6|.(3,6:2 2/5)^3=|-1/6|.(3/2)^3=1/6 . 27/8=9/16`
`4//|(-0,5)^2+7/2|.10-(29/30-7/15):(-2017/2018)^0=|1/4+7/2|.10-1/2:1=|15/4|.10-1/2=15/4 .10-1/2=75/2-1/2=37`
`5// 8/3+(3-1/2)^2-|[-7]/3|=8/3+(5/2)^2-7/3=8/3+25/4-7/3=107/12-7/3=79/12`
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Thực hiện tính
M=\(1+\dfrac{1}{2}\cdot\left(1+2\right)+\dfrac{1}{3}\cdot\left(1+2+3\right)+\dfrac{1}{4}\cdot\left(1+2+3+4\right)+...+\dfrac{1}{16}\cdot\left(1+2+3+...+16\right)\)
6 tháng 8 2021 lúc 17:11
\(A=\left(2\dfrac{1}{3}+3\dfrac{1}{2}\right):\left(-4\dfrac{1}{6}+3\dfrac{1}{7}\right)+7\dfrac{1}{2}\)
\(B=4\dfrac{25}{16}+25\cdot\left(\dfrac{9}{16}:\dfrac{125}{64}\right):\left(-\dfrac{27}{8}\right)\)
giải hộ mk nhanh nhanh nhoa ☺
27 tháng 3 2022 lúc 7:34
P =1+\(\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+\dfrac{1}{4}\left(1+2+3+4\right)+...+\dfrac{1}{16}\left(1+2+3+...+16\right)\)
\(=1+\dfrac{1}{2}\cdot\dfrac{2\cdot3}{2}+\dfrac{1}{3}\cdot\dfrac{3\cdot4}{2}+...+\dfrac{1}{16}\cdot\dfrac{16\cdot17}{2}\)
=1+3/2+4/2+...+17/2
=(2+3+4+...+17)/2
=152/2=76
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Tính :
\(M=1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+\dfrac{1}{4}\left(1+2+3+4\right)+...+\dfrac{1}{16}\left(1+2+3+...+16\right)\)
\(M=1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+...+\dfrac{1}{16}\left(1+2+3+...+16\right)\)
\(M=1+\dfrac{1}{2}.3+\dfrac{1}{3}.6+...+\dfrac{1}{16}.136\)
\(M=1+\dfrac{1}{2}.\dfrac{2.3}{2}+\dfrac{1}{3}.\dfrac{3.4}{2}+...+\dfrac{1}{16}.\dfrac{16.17}{2}\)
\(M=1+\dfrac{3}{2}+\dfrac{4}{2}+...+\dfrac{17}{2}=\dfrac{1}{2}\left(2+3+4+...+17\right)\)
\(M=\dfrac{1}{2}.\left(\dfrac{17.18}{2}-1\right)=\dfrac{1}{2}.152=76\)
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Bài 1 : Thực hiện phép tínha , left(dfrac{1}{2}+dfrac{16}{30}right)-left(1+dfrac{1}{30}right)b , dfrac{-5}{11}.dfrac{4}{13}+dfrac{-5}{11}.dfrac{9}{13}+3dfrac{5}{11}c , 3^2-12.left(dfrac{3}{4}-dfrac{2}{3}right)Bài 2 : Cho đường thẳng xy , lấy điểm O thuộc đường thẳng xy . Trên tia Ox , lấy 2 điểm A , B sao cho OA 3 cm , AB 2 cm a, Trong 3 điểm O , A , B điểm nào nằm giữa 2 điểm còn lại.b, Có tất cả bao nhiêu tia ? nêu tên ?c, Tính độ dài OB ?Bài 3 : Tính A dfrac{9}{1.2}+dfrac{9}{2.3}+dfrac{9}...
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Bài 1 : Thực hiện phép tính
a , \(\left(\dfrac{1}{2}+\dfrac{16}{30}\right)-\left(1+\dfrac{1}{30}\right)\)
b , \(\dfrac{-5}{11}.\dfrac{4}{13}+\dfrac{-5}{11}.\dfrac{9}{13}+3\dfrac{5}{11}\)
c , \(3^2-12.\left(\dfrac{3}{4}-\dfrac{2}{3}\right)\)
Bài 2 : Cho đường thẳng xy , lấy điểm O thuộc đường thẳng xy . Trên tia Ox , lấy 2 điểm A , B sao cho OA = 3 cm , AB = 2 cm
a, Trong 3 điểm O , A , B điểm nào nằm giữa 2 điểm còn lại.
b, Có tất cả bao nhiêu tia ? nêu tên ?
c, Tính độ dài OB ?
Bài 3 : Tính A = \(\dfrac{9}{1.2}+\dfrac{9}{2.3}+\dfrac{9}{3.4}+...+\dfrac{9}{2021.2022}\)
bài 3:
\(A=\dfrac{9}{1\cdot2}+\dfrac{9}{2\cdot3}+\dfrac{9}{3\cdot4}+...+\dfrac{9}{2021\cdot2022}\)
\(=9\left(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+...+\dfrac{1}{2021\cdot2022}\right)\)
\(=9\left(1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{2021}-\dfrac{1}{2022}\right)\)
\(=9\cdot\dfrac{2021}{2022}=\dfrac{6063}{674}\)
Bài 1:
a: \(\left(\dfrac{1}{2}+\dfrac{16}{30}\right)-\left(1+\dfrac{1}{30}\right)\)
\(=\dfrac{15+16}{30}-1-\dfrac{1}{30}\)
\(=\dfrac{30}{30}-1\)
=1-1
=0
b: \(\dfrac{-5}{11}\cdot\dfrac{4}{13}+\dfrac{-5}{11}\cdot\dfrac{9}{13}+3\dfrac{5}{11}\)
\(=-\dfrac{5}{11}\left(\dfrac{4}{13}+\dfrac{9}{13}\right)+3+\dfrac{5}{11}\)
\(=-\dfrac{5}{11}+3+\dfrac{5}{11}\)
=3
c: \(3^2-12\left(\dfrac{3}{4}-\dfrac{2}{3}\right)\)
\(=9-12\cdot\dfrac{9-8}{12}\)
=9-1
=8
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tính \(P=1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+\dfrac{1}{4}\left(1+2+3+4\right)+...+\dfrac{1}{16}\left(1+2+3+...+16\right)\)
\(P=1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+...+\dfrac{1}{16}\left(1+2+3+...+16\right)\\ P=1+\dfrac{1}{2}.\dfrac{2.3}{2}+\dfrac{1}{3}.\dfrac{3.4}{2}+...+\dfrac{1}{16}.\dfrac{16.17}{2}\\ P=1+\dfrac{3}{2}+\dfrac{4}{2}+...+\dfrac{17}{2}\\ P=\dfrac{1}{2}\left(2+3+4+...+17\right)\\ P=\dfrac{1}{2}\left(\dfrac{17.18}{2}-1\right)\\ P=\dfrac{1}{2}.152=76\)
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P = \(1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+\dfrac{1}{4}\left(1+2+3+4\right)+....+\dfrac{1}{16}\left(1+2+3+...+16\right)\)
\(P=1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+...+\dfrac{1}{16}\left(1+2+3+...+16\right)\)
\(=1+\dfrac{1}{2}\left(2\cdot3:2\right)+\dfrac{1}{3}\cdot\left(3\cdot4:2\right)+...+\dfrac{1}{16}\left(16\cdot17:2\right)\)
\(=1+\dfrac{3}{2}+\dfrac{4}{2}+...+\dfrac{17}{2}\)
\(=\dfrac{2+3+4+...+17}{2}=\dfrac{152}{2}=76\)
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18 tháng 10 2017 lúc 18:54
giúp mk vs làm mãi ko ra mk cảm ơn trc.
a)\(P=\dfrac{\dfrac{42}{31}.\dfrac{31}{7}-\left(1.5-6\dfrac{1}{3}.\dfrac{2}{19}\right)}{4\dfrac{5}{6}+\dfrac{1}{6}.\left(12-5\dfrac{1}{3}\right)}.\left(-1:\dfrac{14}{39}\right)\)
b)\(Q=\left(\dfrac{1}{4}-1\right).\left(\dfrac{1}{9}-1\right).\left(\dfrac{1}{16}-1\right).\left(\dfrac{1}{25}-1\right).....\left(\dfrac{1}{121}-1\right)\)