For the function f(x)=1/(x+1), verify f(x) is one-to-one, then calculate f^-1 (1/4) and (f^-1)' (1/4)

Answer 1

the inverse

y=1/(x+1)
x=1/(y+1)
y=1/x -1

y(1/4)=3

y'=-1/x^2
y'(1/4)=-16