CHO A=1/2^2+1/3^2+1/4^2+...+1/100^2 va B=1/4^2+1/6^2+1/8^2+.....+1/200^2khi do A/B=...
nhanh len cac ban oi
cho A=1//2^2+1/3^2+...+1/100^2 va B=1/4^2+1/6^2+...+1/200^2. Khi do A/B=
Giải giúp tớ với :
Cho A = 1/2^2 + 1/3^2 + 1/4^2 + ....+ 1/100^2 va B = 1/4^2 + 1/6^2 + ... + 1/200^2. Vay A/B =
ta có: B=1/4^2 +1/6^2+......+1/200^2
B= 1/2^2 x(1/2^2+1/3^2 +1/4^2+......+1/100^2)
B=1/4 x(A)
suy ra: A/B= A / 1/4 x A
A/B= 4
Cho A = 1/ 2^2 + 1/3^2 + 1/4^2 + .......+ 1/100^2 và B = 1/4^2 + 1/6^2 + 1/8^2 +........+ 1/200^2 . tính A/B = ........
\(B=\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+....+\frac{1}{200^2}=\frac{1}{\left(2.2\right)^2}+\frac{1}{\left(2.3\right)^2}+\frac{1}{\left(2.4\right)^2}+...+\frac{1}{\left(2.100\right)^2}\)
\(B=\frac{1}{2^2.2^2}+\frac{1}{2^2.3^2}+\frac{1}{2^2.4^2}+...+\frac{1}{2^2.100^2}=\frac{1}{2^2}.\frac{1}{2^2}+\frac{1}{2^2}.\frac{1}{3^2}+\frac{1}{2^2}.\frac{1}{4^2}+...+\frac{1}{2^2}.\frac{1}{100^2}\)
\(B=\frac{1}{2^2}.\left(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+....+\frac{1}{100^2}\right)=\frac{1}{4}.A\)
\(\Rightarrow\frac{A}{B}=\frac{A}{\frac{1}{4}A}=\frac{A}{\frac{A}{4}}=A.\frac{4}{A}=4\)
so sanh (a+1).(a+2).(a+3)-a.(a+1).(a+2) va 3(a+1).(a+2)
b,tinh
M=1.2+2.3+3.4+...+ 2002.2003
GIUP MINH NHANH LEN NHE CAC BAN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
so sanh A= 1/2^2 + 1/3^2 + ....... + 1/100^2 va B= 1/4^2 + 1/6^2 +.... +1/200^2
A=1/2^2 +1/3^2+1/4^2+...+1/100^2 và B=1/4^2+1/6^2+1/8^2+...+1/200^2. Tính A/B
A=1/2^2 +1/3^2+1/4^2+...+1/100^2 và B=1/4^2+1/6^2+1/8^2+...+1/200^2. Tính A/B
A = 1/2^2 + 1/3^2 + 1/4^2 + ... + 1/100^2 và B = 1/4^2 + 1/6^2 + 1/8^2 + ...1/200^2. Khi đó A/B = ...
1 a, 3 va 1/5 - 2 va 1/6 + 1/5
b, 5 va 12/13 - 2 va 15/26 + 1/26
c, 7 va 1/12 + 1/12 - 6 va 1/4
2 tinh gia tri bieu thuc
a, 3 va 2/9 - [1 va 5/8 + 1 va 2/9 ] - 3/8
b, 4 va 2/5 - 1 va 3/7 - 1 va 4/7 + 1/5
c, 1 va 9/12 - 5/4 - 1/2
3 tinh
a, 6 nhan 7 nhan 8 nhan 9 nhan 1 tren 18 nhan 16 nhan 14 nhan 12 nhan 2
b, 4 nhan 15 nhan 9 nhan 24 tren 3 nhan 12 nhan 8 nhan 5
4 rut gon cac phan so
a, 96/150 ; 255/408 ; 630/224
b, 1515/1717; 352352/470470; 200620062006/200520052005
5 so sanh cac phan so
a, 7/9 va 9/7 ; b, 135/120 va 13/8; c, 3535/4848 va 5/8 ; d, 650650/480480 va 222222/144144
6, so sanh hai phan so
a, 2005/2006 va 2006/2007 ; b, 2008/2007 va 2007/2006
cac ban lam tung buoc nha