Here 
……….(i)
……..(ii)
And 
= 
……….(iii)
Now 
From eq. (iii),
= 
= 
< 0
is a point of local maxima and maximum value of 
is at .
Show that the function given by f(x)=log (x )/ x has maximum at x = e.
Show that the function given by f(x)=log (x )/ x has maximum at x = e.