How do you find the first and second derivative of # ln(ln x)#?

1 Answer
Sep 11, 2016

Answer:

#1/(xlnx)#

Explanation:

First derviative: #d/dxln(ln(x))#

Chain rule: #d/dxf(g(x))=f'(g(x))*g'(x)#

Let g=ln(x)

#f(g)=ln(g), g(x)=ln(x)#

#f'(g)=1/g, g'(x)=1/x#

#f'(x)=1/ln(a)#

#f'(g(x))*g'(x)=(1/ln(x)*1/x)#

#1/(xlnx)#

Second Derivative: #d/dx(1/ln(x)*1/x)#

Product rule: #f(x)g'(x)+f'(x)g(x)#

#f(x)=1/lnx, g(x)=1/x#

#1/lnxd/dx(x^-1)+d/dx(lnx)^-1(1/x)#

#-1/(x^2lnx)-1/(x^2ln^2(x)#