Equation Icon  2n (A ) f (R) = R − μRc --(R∕Rc-)---- with n, μ,Rc > 0, (4.83 ) ([R∕Rc )2n + 1 ] ( 2 2)−n (B ) f (R) = R − μRc 1 − 1 + R ∕R c with n, μ,Rc > 0. (4.84 )