1/1+2 + 1/1+2+3 + 1/1+2+3+4+.....+1/ 1+2+3+4+.....+2007
Chu y : la phan so
Những câu hỏi liên quan
1/7=8/-x
3x/9=2/6
4/2/5:(-33/10)+x=-1/5/6
(x-2/1/4):(-5/6)=3
-8:(4/1/5x+3/10)=4/4/9
(5,5x-44):(-3/2)=30
(13/10x-15).(-5/14)=3
1/3.(x+5/2)=-2
chu y dau( //)la so tap phan con dau( /) la phan so
\(\frac{4}{\frac{2}{5}}:\left(-\frac{33}{10}\right)+x=-\frac{1}{\frac{5}{6}}\)
\(10:\left(-\frac{33}{10}\right)+x=-\frac{6}{5}\)
\(-\frac{100}{33}+x=-\frac{6}{5}\)
\(x=\frac{302}{165}\)
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cho tong S =4/3+1/4+1/5+...+1/8+1/9
CMR1 <S<2 chu y / la phan so
Cho A=1/2^2+1/3^2+1/4^2+.......+1/20^2 .Chung to rang A<1
Cho A=1/2^2+1/3^2+1/4^2+........+1/20^2 .Chung minh A<1
Chu thich / La phan so
^ la mu
\(Ta\)có :
\(\frac{1}{2^2}< \frac{1}{1.2};\frac{1}{3^2}< \frac{1}{2.3};...;\frac{1}{20^2}< \frac{1}{19.20}\)
\(\Rightarrow\frac{1}{2^2}+\frac{1}{3^2}+...+\frac{1}{20^2}< \frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{19.20}\)
\(\Rightarrow A< 1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{19}-\frac{1}{20}\)
\(\Rightarrow A< 1-\frac{1}{20}< 1\left(Đpcm\right)\)
Chúc bạn học tốt !!!
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1.tim so bi chia trong phep chia cho 12 co thuong la 35 va so du la so le co 2chu so2.hieu cua so lon nhat co 4 chu so khac nhau va so nho nhat co 4 chu sola bao nhieu3.mot hinh chu nhat co chieu dai gap ruoi chieu rong. Neu moi chieu tang them 1m thi duoc hinh chu nhat moi co dien tich tang them 26m2. Tinh chu vi hinh chu nhat4.trung binh cong cua 2 phan so bang 5/12. Phan so thu nhat hon phan so thu hai 1/6. Tim phan so thu nhat5.tim y biet (5/7 - y) nhan 4/5 7/10 + 1/26.hieu 2 so 1/3 so be.To...
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1.tim so bi chia trong phep chia cho 12 co thuong la 35 va so du la so le co 2chu so
2.hieu cua so lon nhat co 4 chu so khac nhau va so nho nhat co 4 chu sola bao nhieu
3.mot hinh chu nhat co chieu dai gap ruoi chieu rong. Neu moi chieu tang them 1m thi duoc hinh chu nhat moi co dien tich tang them 26m2. Tinh chu vi hinh chu nhat
4.trung binh cong cua 2 phan so bang 5/12. Phan so thu nhat hon phan so thu hai 1/6. Tim phan so thu nhat
5.tim y biet (5/7 - y) nhan 4/5 =7/10 + 1/2
6.hieu 2 so =1/3 so be.Tong 2 so la 63. Tim so be
tinh (1+1 1/4+1 1/2+1 3/4 +2+ 2 1/4 2 1/2+ 2 3/4+.......+4 3/4):23
_cac ban chu y : (vi du: 1 1/4 va cac so giong no la hon so
cho day so 1/2 ; 2/1 ; 1/3 ; 2/2 ; 3/1 ; 1/4 ; 2/3 ; 3/2 ; 4/1;.................hoi phan so 1/2017 la so thu bao nhieu trong day
vong huyen day
1.Tim cac chu so x va y de so 1x8y2 chia het cho 36
2.tim cac gia tri nguyen cua n de phan so A=3.n+2/n-1 co gia tri la so nguyen
3.tim cac chu so x y thoa man
(x-2)^2.(x-3)^2=4
4.tim so tu nhien x biet
(x-5):3/100=20.x/100 +5
Bai 1 A; 85+76+59-2B;3-56-49+3224Bai 2; Trong mot thu vien co 12 so sach la truyen thieu nhi 25 so sach la sach giao khoa con lai la cac loai sach khac tim phan so chi so sach khacBai3 ;viet phan so 78 thanh tong cua ba phan so so toi gian co mau so khac nhau Bai4; A;x :54 95+12 B;[x +34]* 57 109Bai 5 mot manh giay hinh chu nhat co chu vi la 223 dm chieu dai hon chieu rong 12 dm tinh dien tich cua manh giay do
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Bai 1
A; 8\5+7\6+5\9-2
B;3-5\6-4\9+32\24
Bai 2; Trong mot thu vien co 1\2 so sach la truyen thieu nhi 2\5 so sach la sach giao khoa con lai la cac loai sach khac tim phan so chi so sach khac
Bai3 ;viet phan so 7\8 thanh tong cua ba phan so so toi gian co mau so khac nhau
Bai4; A;x :5\4 =9\5+1\2 B;[x +3\4]* 5\7 =10\9
Bai 5 mot manh giay hinh chu nhat co chu vi la 22\3 dm chieu dai hon chieu rong 1\2 dm tinh dien tich cua manh giay do
cau 1:tinh gia tri bieu thuc
3/4 +1/1/4 *2/2/3-(-1/2)^2:6/5
cho ma co 2 dau/la hon so,con 1 dau la phan so,con ^2 la mu 2
cau 2:tim x biet
( x-1)^5= -32
cho ^5 co nghia la mu 5
a)3/4+1/1/4*2/2/3-(-1/2)^2:6/5
=3/4+5/4*8/3-1/4:6/5
=3/4+10/3-5/24=18/24+80/24-5/24=93/24=31/8
b)(x-1)^5=32=2^5
=>x-1=2
x=2+1
x=3
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