Quarter-wave and tappered-line impedance transformers

I was wondering if any would be kind enough in assiting me to derive an expression for the input reflection coefficient between reflection coefficient and impedance for a single-section transformer with an output resistive load Zo1=(ZoRL), RL=Load Resistance; Zo = output impedance. There is a magnitude of input reflection coefficient equal to

|Tin| = {1 + 4N/((N-1)^2cos^2Bl)} ==|N-1|/(2(N)^1/2)*|cosBl|

where l = lambda/4 at the design frequency

N= RL/Zo

and the approximate form is valid for Bl near pi/2 rad.