In order to get the tangent line, we need the point ( 1 , f − 1 ( 1 ) ) {\displaystyle (1,f^{-1}(1))} , and the derivative of f − 1 ( x ) {\displaystyle f^{-1}(x)} at -1.
Recall the relationship between f − 1 ( 1 ) {\displaystyle f^{-1}(1)} and f ( x ) = 1 {\displaystyle f(x)=1} .
