exo7 1223

$\displaystyle { f :x \mapsto \hbox{sin }(\frac{1}{ x }) }$ si $x\not = 0$ et $f(0)=0 .$

$\displaystyle { g :x \mapsto x \hbox{sin }(\frac{1}{ x }) }$ si $x\not = 0$ et $f(0)=0 .$

$\displaystyle { h :x \mapsto x^2 \hbox{sin }(\frac{1}{ x }) }$ si $x\not = 0$ et $f(0)=0 .$