### tangent to inverse function?

Posted:

**Wed Aug 03, 2011 2:24 am**Dear All

For the function 'f' as :

f(x)=x - 1/x ; x >0

for which value of 'a' the line '2y-x=a' is tangent to the curve of f^(-1) (inverse function of f)?

Thank you

For the function 'f' as :

f(x)=x - 1/x ; x >0

for which value of 'a' the line '2y-x=a' is tangent to the curve of f^(-1) (inverse function of f)?

Thank you