[en] The present work presents some analytical expressions for the temperature distribution in a rectangular fin besides the effectiveness of a fin operating at single mode of heat transfer along its length. The fin heat transfer coefficient is taken as a power function of the temperature difference between the fin and the working fluid (hα(θ)ⁿ) Unlike the previous solutions obtained by Unal et al, which were restricted to some values of the exponent n, the present expressions for the fin temperature distribution cover all values of lying in the three ranges : n > 0, n < -2 and -2 < n < 0. For the first two ranges an expressions for the maximum fin effectiveness is obtained.3 fig., 2 tab