How do you find the derivative of #ln (1 - x^2)#?

1 Answer
Mar 17, 2018

Derivative of #ln(1-x^2)# is #-(2x)/(1-x^2)#

Explanation:

We use te concept of function of a function. If we have #f(g(x))#, then

#(df)/(dx)=(df)/(dg(x))xx(dg)/(dx)#

Here we can write #f(x)=ln(1-x^2)# as #f(x)=ln(g(x))#, where #g(x)=1-x^2#

Now as #f(x)=ln(g(x))#, #(df)/(dg(x))=1/(g(x))#

and #(dg)/(dx)=-2x# and hence

#(df)/(dx)=1/(g(x))xx(-2x)=(-2x)/(g(x))=-(2x)/(1-x^2)#