f (x) = xx has a stationary point at

Given equation is f (x) = xx


Let y= xx………(i)


Taking logarithm on both sides we get


log y=log (xx)


log y=x log x


Now applying first derivative, we get



Now applying the product rule of differentiation we get



Now applying the deravative we get




Substituting the value of y from equation (i), we get



Now we will find the critical point by equating equation (i) to 0, we get


xx (1+log x)=0


1+log x =0 as xx cannot be equal to 0


log x=-1


But -1=log e-1


log x=log e-1


Equating the terms we get


x= e-1



Hence f(x) has a stationary point at


So the correct option is option B.

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