tinh a=1/2+1/4+1/8+1/16+.....(tong co 10so hang)
a=...(viet phan so toi gian)
tinh a = 1/2 + 1/4 + 1/8 + 1/16 + ... (biet tong tren co 10 so hang)
a=1/2+1/4+1/8+1/16+...+1/1024
=1023/1024
\(\frac{1023}{1024}\)
MÃi mãi có một tương lai tươi sáng
tinh a=1/4+1/8+1/16+....{tong co 10 so hang}
1/4+1/8+1/16+...
=1/4+1/8+1/16+1/32+1/64+1/128+1/256+1/512+1/1024+1/2048
=1/2-1/4+1/4-1/8+1/8-1/16+1/16-1/32+1/32-1/64+1/64-1/128+1/128-1/256+1/256-1/512+1/512-1/1024+1/1024-1/2048
=1/2-1/2048
=1024/2048-1/2048
=1023/2048
BAI 3 ;TRONG mot thu vien co 1\2 so sach la truyen thieu nhi 2\5 so sach la sach giao khoa con lai la sach giao khoa tim phan so chi so sach khac
BAI 4; viet phan so 7\8 thanh tong cua ba phan so toi gian co mau so khac nhau
a, Viet phan so 7/8 duoi dang tong cua 3 phan so co cung tu so
b, Tinh: ( 1- 1/2 )x(1 - 1/3 )x(1- 1/4 )x(1 - 1/5 )
a) đây chỉ là 1 trong nhiều cách
\(\frac{7}{8}=\frac{1}{8}+\frac{4}{8}+\frac{2}{8}\)
a) \(\frac{7}{8}=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}\)
b) \(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right).\left(1-\frac{1}{5}\right)\)
\(=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.\frac{4}{5}\)
\(=\frac{1.2.3.4.}{2.3.4.5}\)
\(=\frac{1}{5}\)
( Dấu chấm là dấu nhân nha bạn )
1.cho hai phan so co tong bang -3 va tich bang 12/5. tinh tong cac nghich daao cua hai phan so do
2.cho hai phan so toi gian a/b va c/d. biet a/b+c/d E z. chung minh /b/=/d/
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
A = 1/4 + 1/2 + 1/8 + 1/16 + ...( tong co 10 so hang )
tong tren co 10 so hang suy ra ps cuoi cung la 1/2014
Suy ra tong=1023/1024
2A=\(2x\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}+\frac{1}{256}+\frac{1}{512}+\frac{1}{1024}\right)\)
2A=\(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}+\frac{1}{256}+\frac{1}{512}\)
2A-A=\(1-\frac{1}{1024}\)
A=\(\frac{1023}{1024}\)
viet phan so 1/2 thanh tong cua hai phan so toi gian khac nhau (tim hai cach viet khac nhau
tim a biet a=1/2+1/4+1/8+1/16+....[tong co 10 so hang]
a = 1/2+1/4+1/8+1/16
= (1 - 1/2) + (1/2 -1/4) + (1/4 - 1/8) + ... + (1/512 - 1/1024).
= 1 - 1/1024
= 1023/1024
A=1/2+1/4+1/8+1/16
A=1/2+(1/2-1/4)+(1/4-1/8)+(1/8-1/16)+....+(1/512-1/1024)
=1/2+1/2-1/1024
=1-1/1024=1023/1024
DS : 1023/1024
a = 1/2 + 1/4 + 1/8 + 1/16
= ( 1 - 1/2 ) + ( 1/2 - 1/4 ) + ( 1/4 - 1/8) + ... + ( 1/512 - 1/1024 )
= 1 - 1/1024
= 1023/1024