Tinh hop li (neu co the)
(1-1/3).(1-1/6).(1-1/10)......(1-1/190)
1/4 - 1/3+ 5/12 Thuc hien cac phep tinh (tinh hop li neu co the)
\(\dfrac{1}{4}-\dfrac{1}{3}+\dfrac{5}{12}\\ =\dfrac{3}{12}-\dfrac{4}{12}+\dfrac{5}{12}\\ =\dfrac{3-4+5}{12}\\ =\dfrac{4}{12}\\ =\dfrac{1}{3}\)
cac ban giup toi cau nay voi:
Thuc hien phep tinh(hop ly neu co the):
(10/99+11/199-12/299)x(1/2-1/3+-1/6)
mong cac ban giup minh nhanh voi a. Minh xin cam on
\(\left(\frac{10}{99}+\frac{11}{199}-\frac{12}{299}\right)\times\left(\frac{1}{2}-\frac{1}{3}+-\frac{1}{6}\right)\)
\(=\left(\frac{10}{99}+\frac{11}{199}-\frac{12}{299}\right)\times\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)
\(=\left(\frac{10}{99}+\frac{11}{199}-\frac{12}{299}\right)\times\left(\frac{3}{6}-\frac{2}{6}-\frac{1}{6}\right)\)
\(=\left(\frac{10}{99}+\frac{11}{199}-\frac{12}{299}\right)\times0\)
\(=0\)
A=-[-806-(-791)+2012]-(806-1791)
B=9-(119).34+119.(-77)-(-119).11
C=-(-2^4)+(-3)^3-(-1)^2011
tinh hop li (neu co the)
giup mik voi ! Ai dung mik tick cho
A = - [-806 - (-791) + 2012] - (806 - 1791)
A = 806 - 791 + 2012 - 806 + 1791
A = (806 - 806) + (1791 - 791)
A = 1000
B = 9 - (119).34 + 119.(-77) - (-119).11
B = 9 - 119(34 + 77 - 11)
B = 9 - 119.100
B = 9 - 11900
B = - 11891
C = -( -24) + (-3)3 - (-1)2011
C = 16 - 27 + 1
C = (16 + 1) - 27
C = 17 - 27
C = -10
tnh bang cach hop li neu co the
1/2*3 +1/3.4 + 1/4*5 + ..... + 1/39*40
giup minh voi nhe mai phai nop rui
\(\text{ta có: }\frac{1}{2.3}=\frac{1}{2}-\frac{1}{3}\)
\(\frac{1}{3.4}=\frac{1}{3}-\frac{1}{4}\)
\(\frac{1}{4.5}=\frac{1}{4}-\frac{1}{5}\)
...........................
\(\frac{1}{39.40}=\frac{1}{39}-\frac{1}{40}\)
Đồng nhất 2 vế ta có:
\(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+....+\frac{1}{39}-\frac{1}{40}=\frac{1}{2}-\frac{1}{40}=\frac{19}{40}\)
Ta có :
\(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{39.40}\)
\(=\)\(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{39}-\frac{1}{40}\)
\(=\)\(\frac{1}{2}-\frac{1}{40}\)
\(=\)\(\frac{20}{40}-\frac{1}{40}\)
\(=\)\(\frac{19}{40}\)
Vậy \(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{39.40}=\frac{19}{40}\)
Giup minh voi ! Tinh hop ly, neu co the.
12-12+11+10-9+8-7+5-4+3+2-1.
=18. Câu này không liên quan đến cấp 2 nhé:))
12-12+11+10-9+8-7+5-4+3+2-1
=-(12+12-11-10)-(9-8+7-5)+(4-3-2+1)
=(-3)-3+0
=(-6)
Chúc bn học tốt
Mk nhầm nha
Dấu ngoặc đầu tiên không có dấu trừ đằng tr bn sửa lại nha
Chúc bn học tốt
co 20 bi do,30 bi trang va mot so bi xanh, tat ca de trong hop. neu lay ra 1 bi trong hop thi co hoi co the lay duoc 1 bi xanh la 9/11.tinh so bi xanh
\(\frac{-7}{25}+0,25.\frac{10}{19}+\frac{1}{4}.\frac{9}{19}+\frac{18}{25}\)
Tinh hop ly neu co the
\(-\frac{7}{25}+0,25.\frac{10}{19}+\frac{1}{4}.\frac{9}{19}+\frac{18}{25}\)
\(=\frac{-7+18}{25}+\frac{1}{4}.\frac{10}{19}+\frac{1}{4}.\frac{9}{19}\)
\(=\frac{11}{25}+\frac{19}{4.19}\)
\(=\frac{11}{25}+\frac{1}{4}\)
\(=\frac{69}{100}\)
1 thuong gia co the xep 8 hop lon hoac 10 hop nho vao 1 thung giay de chuyen hang . Trong 1 lan giao hang,anh ta gui di tat ca 96 hop . Neu so hop lon nhieu hon so hop nho thi co tat ca bao nhieu thung ma nguoi do da gui di
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