Ket qua cua tong: A = 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 = ............
Ai giai nhanh nhat va ghi ro cach lam ra ( ko ghi ....... ) thi minh se tick cho nha, minh dang can gap^^^
Giup minh voi!
1/2^2 + 1/4^2 + 1/6^2 +.....+ 1/210^2 (Nho ghi cach giai ro rang)
Ai nhanh nhat minh se tick cho nhung phai dung do! Thank truoc nha!
Intelligent help voi! Lam on di ma minh dang can gap lam!
mot soi day cat lam 4 doan
doan thu nhat bang 1/3 tong do dai 3 doan con lai
doan thu hai bang 1/4 tong do dai 3 doan con lai
doan thu ba bang 1/5 tong do dai 3 doan con lai
Va biet doan thu nhat dai hon doan thu hai la 6 met
a) tinh do dai doan day
b)tinh do dai moi doan
ghi ro cach giai ai nhanh nhat thi minh se ket ban
tim 2 so co tong gap 5 lan hieu va = 1/6 tich cua chung
giai lun cho minh nha ghi ro cach lam ,bai giai ra y
Bai 1 : Tim UCLN cua :
a ) 1 va 10
b ) 11 va 15
c ) 18 va 42
d ) 24 ,16 va 8Ai lam nhanh va dung minh se tick cho nha ,minh dang can gap .
a) 1 = 1
10 = 2 . 5
ƯCLN(1, 10) = 1
b) 11 = 11
15 = 3 . 5
ƯCLN(11, 15) = 1
c) 18 = 2 . 32
42 = 2 . 3 . 7
ƯCLN(18, 42) = 2 . 3 = 6
d) 24 = 23 . 3
16 = 24
ƯCLN(24, 16) = 23 = 8
a)ƯCLN (1,10)={1}
b)ƯCLN (11,15)={1}
c)Ta có :18=2.32
42=2.3.7
\(\Rightarrow\)ƯCLN(18,42)=2.3=6
d)Ta thấy: 24 ;16;8 \(⋮\)8 \(\Rightarrow\)ƯCLN (24;16;8)=8
Bài làm :
a ) UCLN ( 1 , 10 ) = 1 . ( Vì 1 chỉ có 1 ước duy nhất là chính nó .)
b ) UCLN ( 11 , 15 ) = 1 ( Vì 2 số trên là 2 số nguyên tố cùng nhau .)
c ) 18 = 2 . 32
42 = 2 . 3 . 7
UCLN ( 18 , 42 ) = 2 . 3 = 6 .
d ) 24 = 23 . 3
16 = 24
UCLN ( 24 , 16 ) = 23 = 8 .
Chúc bạn học tốt Toán !
A=1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
Ai nhanh nhat minh se tik cho nha nhan len nhe
A=1/2+1/6+....+1/56+1/72
A=1/1.2+1/2.3+...+1/7.8+1/8.9
A=1/1-1/2+1/2-1/3+...+1/7-1/8+1/8-1/9
A=1/1-1/9=9/9-1/9=8/9
A=\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+..\frac{1}{8.9}\)
A=\(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+..+\frac{1}{8}-\frac{1}{9}\)
A=1-\(\frac{1}{9}\)=\(\frac{8}{9}\)
can thu nhat bang 40%can thu hai.nguoi ta do 3 lit cua can thu hai sang can thu nhat thi hai can bang nhau.tinh tong so lit cua 2 can luc dau.
cac bn ghi cach giai cho to,ai lam dung va nhanh nhat mk tick
1.tinh
A= 1/2 +5/6 +11/12 +19/20 +29/30 +41/42 +55/56 + 71/72 + 89/90
Ai lam dung va nhanh nhat minh se like !!!!!!!!!!!!!!!!!!!!!!!!!
A = \(\frac{1}{2}+\frac{5}{6}+\frac{11}{12}+...+\frac{89}{90}\)
A = \(\frac{1}{2}+\left(1-\frac{1}{6}\right)+\left(1-\frac{1}{12}\right)+...+\left(1-\frac{1}{90}\right)\)
A = \(\left(1+1+...+1\right)-\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{90}\right)\)
A = \(9-\left(\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{9.10}\right)\)
A = \(9-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+....+\frac{1}{9}-\frac{1}{10}\right)\)
A = \(9-\left(1-\frac{1}{10}\right)=9-\frac{9}{10}\)
A = \(\frac{81}{10}\)
\(A=\frac{1}{2}+\frac{5}{6}+\frac{11}{12}+...+\frac{89}{90}=\left(1-\frac{1}{2}\right)+\left(1-\frac{1}{6}\right)+\left(1-\frac{1}{12}\right)+...+\left(1-\frac{1}{90}\right)\)
\(=\left(1+1+1+...+1\right)-\left(\frac{1}{2}+\frac{1}{6}+...+\frac{1}{90}\right)=10-\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{9.10}\right)\)
\(=10-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{9}-\frac{1}{10}\right)=10-\left(1-\frac{1}{10}\right)=10-\frac{9}{10}=\frac{91}{10}\)
\(\frac{1}{2}+\frac{5}{6}+\frac{11}{12}+\frac{19}{20}+...+\frac{89}{90}\)
\(=1-\frac{1}{2}+1-\frac{1}{6}+1-\frac{1}{12}+1-\frac{1}{20}+...+1-\frac{1}{90}\)
\(=9-\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{90}\right)\)
\(=9-\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{9.10}\right)\)
\(=9-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{9}-\frac{1}{10}\right)\)
\(=9-\left(1-\frac{1}{10}\right)\)
\(=9-\frac{9}{10}=\frac{81}{10}\)
Tinh nhanh:
1/6+1/12+1/20+1/30+1/42+1/56
Lam di nha ai lam nhanh thi minh tick!
Tổng quát: \(\frac{1}{n\left(n+1\right)}=\frac{1}{n}-\frac{1}{n+1}\)
Ta có: \(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}\)
\(=\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}\)
\(=\frac{1}{2}-\frac{1}{8}=\frac{3}{8}\)
1/6+1/12+1/20+1/30+1/42+1/56
=1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=1/2-1/8
=3/8
cho hai so nguyen duong co ti so la 7:3 va tich cua chung la 21. Hai so do co tong binh phuong la......
Co cach lam cu the nha!!! minh se cho 1 tick!! mau len nhe!!!! minh dang gap!!!
gọi hai số đó là a và b
ta có 7a.3b=21=> (a.b) .(7.3) =21=> a.b = 21:21=> a.b= 1 ma tất cả các số nhân với 1 sẽ bằng 1 nên sẽ không có tổng bình phương