Respuesta :

Let [tex]n=7[/tex]. Then

[tex]3(7)=21<5040=7![/tex]

Assume the inequality holds for [tex]n=k[/tex], so that [tex]3k<k![/tex]. Then for [tex]n=k+1[/tex], you have, for [tex]k>7[/tex],

[tex]3(k+1)<3k(k+1)<k!(k+1)=(k+1)![/tex]

so the statement is true.