ta có \(A=\frac{2}{0,\left(1998\right)}+\frac{2}{0,0\left(1998\right)}+\frac{2}{0,00\left(1998\right)}=\frac{2}{0,\left(1998\right)}+\frac{2}{0,\left(1998\right)}.\frac{1}{10}+\frac{2}{0,\left(1998\right)}.\frac{1}{100}\)
\(=\frac{2}{0,\left(1998\right)}.\left(1+\frac{1}{10}+\frac{1}{100}\right)=\frac{2}{0,\left(1998\right)}.1\frac{11}{100}=\frac{222}{0,00\left(1998\right)}\)
Tính?
\(A=\frac{1}{0,\left(93\right)}+\frac{1}{0,0\left(93\right)}+\frac{1}{0,00\left(93\right)}\)
Bài 1: Tính
a)\(\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right).....\left(1-\frac{1}{n+1}\right)\)
b)\(\frac{1}{2000.1999}-\frac{1}{1999-1998}-\frac{1}{1998-1997}-...-\frac{1}{3.2}-\frac{1}{2.1}\)
c)\(-3+\frac{1}{1+\frac{1}{3+\frac{1}{1+\frac{1}{3}}}}\)
ai onl giai gap cho mk voi nha!
Tim x,y, biet :
\(\left(x+\frac{1}{2}\right)^2+\left(y-\frac{1}{2}\right)^{1998}=0\)
1. Tính
a) 6/5 + 6/35 - 6/125 - 6/2009 - 6/2011
7/5 + 7/35 + 7/125 + 7/2009 + 7/2011
b)\(\left(1-\frac{1}{2^2}\right)\left(1-\frac{1}{3^2}\right)\left(1-\frac{1}{4^2}\right)...\left(1-\frac{1}{1998^2}\right)\)
Cho \(\frac{a}{b+c}=\frac{c}{a+b}=\frac{b}{c+a}\) (a,b,c khác 0)
Tính \(20\cdot\left(\frac{a}{b+c}\right)+3\cdot\left(\frac{c}{a+b}\right)+1998\cdot\left(\frac{b}{c+a}\right)\)
Cho ba số x,y,z thỏa mãn \(\frac{x}{1998}=\frac{y}{1999}=\frac{z}{2000}\).CMR:\(\left(x-z\right)^3=8\left(x-y\right)^2\left(y-z\right)\)
1.Tính
a) \(\frac{6}{5}+\frac{6}{35}-\frac{6}{125}-\frac{6}{2009}-\frac{6}{2011}\)
______________________________________
\(\frac{7}{5}+\frac{7}{35}+\frac{7}{125}+\frac{7}{2009}+\frac{7}{2011}\)
b) \(\left(1-\frac{1}{2^2}\right).\left(1-\frac{1}{3^2}\right).\left(1-\frac{1}{4^2}\right)....\left(1-\frac{1}{1998^2}\right)\)
giúp mình với.Cảm ơn trước nha
thuc hien phep tinh
\(\left[6-3.\left(-\frac{1}{3}^2\right)+\sqrt{0,25}\right]:\sqrt{0,\left(9\right)}\)
\(\left(\frac{1}{2}\right)^2.\sqrt{16}-3^2.\sqrt{0,01}+\left(2^2\right)^2-\left(0,0\left(6\right)\right)+\frac{13}{30}\)
Tìm x,biết:
\(a,\)\(\left(2\frac{1}{3}+3\frac{1}{2}\right):\left(x+3\frac{1}{7}\right)+7\frac{1}{2}=1\frac{69}{86}\)
\(b,\left(7+0,00.x\right):24,7-12,3=77,7\)
\(c,\left(\left(6\frac{3}{7}-\frac{0,75-2}{0,35}\right).2,8+1,75\right):0,05=2,35\)
