Derive a formula for equivalent resistance

[boo_lufc]

Is it possible to derive a formula for the equivalent resistance of n such sections in cascade?
Show your analysis.

Series: Reqv = R1 + R2 +...Rn

Parallel: Reqv = 1/{(1/R1) + (1/R2) + (1/R3) +...(1/Rn)}

 

[berkeman]

Is it possible to derive a formula for the equivalent resistance of n such sections in cascade?
Show your analysis.

Series: Reqv = R1 + R2 +...Rn

Parallel: Reqv = 1/{(1/R1) + (1/R2) + (1/R3) +...(1/Rn)}

...and how would you go about attempting to solve this? What is the resistance of one stage? And the resistance of two stages in series? And...

 

[boo_lufc]

I was thinking Rn is the last resistor so the last branch of any similar circuit would be
Rn + Rn-1 in series
Then this would be in parallel with Rn-2 + Rn-3 and so on
i.e Reqv = 1/ {(1/Rn + Rn-1) + (1/(Rn-2 + Rn-3) + (Rn-4 + Rn-5)}
Is this along the right lines at