cho a =\(\frac{2008}{2009}\),b=\(\frac{2009}{2008}\),c=\(\frac{1}{2009}\),d=\(\frac{2007}{2008}\)tính a-b+c+d
CHO A=\(\frac{2008}{2009};b=\frac{2009}{2008};c=\frac{1}{2009};d=\frac{2007}{2008}\)
tính a - b + c + d
a-b+c+d=\(\frac{2008}{2009}-\frac{2009}{2008}+\frac{1}{2009}+\frac{2007}{2008}=\left(\frac{2008}{2009}+\frac{1}{2009}\right)-\left(\frac{2009}{2008}-\frac{2007}{2008}\right)=1-\frac{2}{2008}=\frac{2006}{2008}=\frac{1003}{1004}\)
\(a-b+c+d=\frac{2008}{2009}-\frac{2009}{2008}+\frac{1}{2009}+\frac{2007}{2008}\)
\(=\left(\frac{2008}{2009}+\frac{1}{2009}\right)+\left(\frac{2007}{2008}-\frac{2009}{2008}\right)=\frac{2009}{2009}+\frac{-2}{2008}\)
\(=1+\frac{-1}{1004}=\frac{1004}{1004}+\frac{-1}{1004}=\frac{1003}{1004}\)
Cho: a = \(\frac{2008}{2009}\) ; b = \(\frac{2009}{2008}\) ; c = \(\frac{1}{2009}\) ; d = \(\frac{2007}{2008}\)
Tìm : a - b+c+d
Có :\(a-b=\frac{2008}{2009}-\frac{2009}{2008}\)\(=\frac{2008^2-2009^2}{2008\cdot2009}=\frac{\left(2008-2009\right)\left(2008+2009\right)}{2008\cdot2009}\)
\(=\frac{-2008-2009}{2008\cdot2009}=-\frac{1}{2009}-\frac{1}{2008}\)
=>a-b+c+d=\(-\frac{1}{2009}-\frac{1}{2008}+\frac{1}{2009}+\frac{2007}{2008}\)
\(=-\frac{1}{2008}+\frac{2007}{2008}=\frac{2006}{2008}=\frac{1003}{1004}\)
tính tổng sau :\(c=\frac{\frac{1}{2008}-\frac{1}{2009}-\frac{1}{2010}}{\frac{5}{2008}-\frac{5}{2009}-\frac{5}{2010}}+\)\(\frac{\frac{2}{2007}-\frac{2}{2008}-\frac{2}{2009}}{\frac{3}{2007}-\frac{3}{2008}-\frac{3}{2009}}\)
\(C=\frac{\frac{1}{2008}-\frac{1}{2009}-\frac{1}{2010}}{\frac{5}{2008}-\frac{5}{2009}-\frac{5}{2010}}+\frac{\frac{2}{2007}-\frac{2}{2008}-\frac{2}{2009}}{\frac{3}{2007}-\frac{3}{2008}-\frac{3}{2009}}\)
\(=\frac{\frac{1}{2008}-\frac{1}{2009}-\frac{1}{2010}}{5.\left(\frac{1}{2008}-\frac{1}{2009}-\frac{1}{2010}\right)}+\frac{2.\left(\frac{1}{2007}-\frac{1}{2008}-\frac{1}{2009}\right)}{3.\left(\frac{1}{2007}-\frac{1}{2008}-\frac{1}{2009}\right)}\)
\(=\frac{1}{5}+\frac{2}{3}\)
\(=\frac{13}{15}\)
so sánh 2008 với tổng 2009 số hạng sau\(s=\frac{2008+2007}{2009+2008}+\frac{^{2008^2+2007^2}}{2009^2+2008^2}+.....+\frac{2008^{2009}+2007^{2009}}{2009^{2009}+2008^{2009}}\)
tính phép tính sau:
\(\frac{2008}{2009}-\frac{2009}{2008}+\frac{1}{2009}+\frac{2007}{2008}\)
=2008/2009-2009/2008+1/2009+2007/2008
=(2008/2009+1/2009)-(2009/2008-2007/2008)
=1-1/1004
=1003/1004
\(\frac{2008}{2009}-\frac{2009}{2008}+\frac{1}{2009}+\frac{2007}{2008}\)
=\(\left(\frac{2008}{2009}+\frac{1}{2009}\right)-\left(\frac{2009}{2008}-\frac{2007}{2008}\right)\)
=\(1-\frac{2}{2008}\)
=\(1-\frac{1}{1004}\)
=\(\frac{1003}{1004}\)
Chúc bn làm tốt nha!!!
tính nhanh : \(\frac{2007}{2008}\times\frac{1}{2009}+\frac{2007}{2008}:\frac{2009}{2008}+\frac{1}{2008}\)
2007/2008 x 1/2009 + 2007/2008 : 2009/2008 + 1/2008
= 2007/2008 x 1/2009 + 2007/2008 x 2008/2009 + 1/2008
= 2007/2008 x (1/2009 + 2008/2009) + 1/2008
= 2007/2008 x 1 + 1/2008
= 2007/2008 + 1/2008
= 2008/2008 = 1
Cho a=2008/2009 b=2009/2008 c=1/2009 d=2007/2008. Tính a-b+c+d
\(a-b+c+d=\frac{2008}{2009}-\frac{2009}{2008}+\frac{1}{2009}+\frac{2007}{2008}\)
\(=\left(\frac{2008}{2009}+\frac{1}{2009}\right)-\left(\frac{2009}{2008}-\frac{2007}{2008}\right)\)
\(=1-\frac{2}{2008}\)
\(=\frac{1003}{1004}\)
Tính:
\(\frac{2007}{2008}+\frac{1}{2009}+\frac{2007}{2008}:\) \(\frac{2009}{2008}+\frac{1}{2008}\)
\(=\left(\frac{2007}{2008}+\frac{1}{2008}\right)+\left(\frac{2007}{2008}.\frac{2008}{2009}+\frac{1}{2009}\right)\)
\(=1+\frac{2008}{2009}=\frac{4017}{2009}\)
\(\frac{2007}{2008}+\frac{1}{2009}+\frac{2007}{2008}:\frac{2009}{2008}+\frac{1}{2008}\)
\(=\frac{2007}{2008}+\frac{1}{2009}+\frac{2007}{2009}+\frac{1}{2008}\)
\(=\left(\frac{2007}{2008}+\frac{1}{2008}\right)+\left(\frac{2007}{2009}+\frac{1}{2009}\right)\)
\(=1+\frac{2008}{2009}\)
\(=\frac{4017}{2009}\)
Bài 1 ; Cho a=2008/2009:b=2009/2008:c=1/2009:d=2007/2008. Tính a-b+c+d