Làm ơn giúp em với ạ???????????? Question Làm ơn giúp em với ạ???????????? in progress 0 Môn Toán Sapo 4 years 2020-10-31T15:10:51+00:00 2020-10-31T15:10:51+00:00 2 Answers 62 views 0
Answers ( )
$f(x)=x^2-(2m+1)x+1$
$\Rightarrow f(-x)=(-x)^2-(2m+1).(-x)+1$
$=x^2+(2m+1)x+1$
Để hàm số chẵn, $f(-x)=f(x)$
$\Rightarrow x^2-(2m+1)x+1=x^2+(2m+1)x+1$
$\Leftrightarrow -(2m+1)x=(2m+1)x$
$\Leftrightarrow 2x(2m+1)=0$
$\Leftrightarrow 2m+1=0$
$\Leftrightarrow m=\dfrac{-1}{2}$
$y=x^2-(2m+1)x+1$ là hàm chẵn
`=>` $2m+1=0$
`<=>` $m=\dfrac{-1}{2}$