Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: f(x)=x^2105-2012x^2014+2012x^2013-…+2012x-1 tính f(2011)

Toán Lớp 8: f(x)=x^2105-2012x^2014+2012x^2013-…+2012x-1 tính f(2011)

Comments ( 2 )

  1. Giải đáp:
     f(2011)=2010
    Lời giải và giải thích chi tiết:
     f(x)=x^{2015}-2012x^{2014}+2012x^{2013}-….+2012x-1
          =(x^{2015}-2011x^{2014})-(x^{2014}-2011x^{2013})+…+(x-2011)+2010
          =x^{2014}(x-2011)-x^{2013}(x-2011)+…..+(x-2011)+2010
          =(x-2011)(x^{2014}-x^{2013}+……+1) +2010
    ->f(2011)=(2011-2011)(2011^{2014}-2011^{2013}+….+1)+2010
                   =0(2011^{2014}-2011^{2013}+….+1)+2010
                   =0+2010
                   =2010
    Vậy f(2011)=2010

  2. $f(x)=x^{2015}-2012x^{2014}+2012x^{2013}-…+2012x-1$
    $=x^{2015}-2011x^{2014}-x^{2014}+2011x^{2013}+…-x^{2}+2011x+x-1$
    $=x^{2014}(x-2011)-x^{2013}(x-2011)+…-x(x-2011)+x-1$
    Thay $x=2011$ vào $f(x)$ ta được:
    $f(x)=x^{2014}.0-x^{2013}.0+…-x.0+2011-1=2010$
     

Leave a reply

222-9+11+12:2*14+14 = ? ( )