tim x x+3/2013+x+2/2012+x+1/2011+3=0 giãi chi tiết
1 x 2 x 3 x ................x 2012 x 2013 - 1 x 3 x 5 x..............x 2011 x 2013 .
(Làm chi tiết nha)
Ta có : 1 x 2 x 3 x ..... x 2012 x 2013 - 1 x 3 x 5 x ..... x 2011 x 2013
= (1 x 3 x 5 x ..... x 2013) x (2 x 4 x 6 x ..... x 2012) - 1 x 3 x 5 x ..... x 2011 x 2013
= (1 x 3 x 5 x ..... x 2011 x 2013) x (2 x 4 x 6 x ..... x 2012 - 1)
a)2^x+2^x+1+2^x+2+2^x+3=480
b)(1/2+1/3+...+1/2012+1/2013)*x=2012/1+2011/2+2010/3+..+2/2011+1/2012
tìm x (1/2+1/3+...+1/2013) *x= 2012 +2011/2+2010/3+...+2/2011+1/2012
tìm x,biet(1/2+1/3+.............+1/2012+1/2013).x=2012/1+2011/2+2010/3+......+2/2011+1/2012
Tìm x biết (1/2+1/3+...+1/2012+1/2013).x = 2012/1+2011/2+2010/3+...+2/2011+1/2012
tìm x biết ( 1/2 + 1/3 + ... + 1/2012 + 1/2013 ) .x = 2012/1 + 2011/2 + 2010/3 + ... + 2/2011 + 1/2012
tìm X biết : ( 1 / 2 + 1/3 + ........+ 1 /2012 + 1/2013 ) . x = 2012/1 + 2011/2 + 2010 /3 + .....+2/2011+1/2012
(x+1\2014)+(x+2\2013)+(x+3\2012)+(x+1\2011)=0
Giải giúp mình với.Cảm ơn
\(\frac{x+1}{2014}+\frac{x+2}{2013}+\frac{x+3}{2012}+\frac{x+4}{2011}=0\)
\(\Leftrightarrow\left(\frac{x+1}{2014}+1\right)+\left(\frac{x+2}{2013}+1\right)+\left(\frac{x+3}{2012}+1\right)+\left(\frac{x+4}{2011}+1\right)=0+1+1+1+1\)
\(\Leftrightarrow\frac{x+2015}{2014}+\frac{x+2015}{2013}+\frac{x+2015}{2012}+\frac{x+2015}{2011}=4\)
\(\Leftrightarrow\left(x+2015\right).\left(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}+\frac{1}{2011}\right)=4\)
\(\Leftrightarrow x+2015=4:\left(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}+\frac{1}{2011}\right)\)
\(\Leftrightarrow x+2015=2012,499379\)
\(\Leftrightarrow x=2012,499379-2015\)
\(\Leftrightarrow x=-2,5006118\)
P/s : Số xấu quá !
Hãy chứng minh A = B , biết:
A = 1 + (1+ 2) + (1+ 2+ 3) + ...........+ ( 1+ 2+ 3+ 4+ ...+ 2013)
B = 2013 x 1 + 2012 x 2 + 2011 x 3 + ......+ 2 x 2012 + 1 x 2013