Self doubt on Ethernet LAN

Question

Are the below formulas for correct w.r.t ethernet LAN?

efficiency :

PD = propagation delay

TD = transmission delay

L = frame size

$\eta =\frac{1}{1 + 6.44(\frac{ pd }{ td })}$ 

throughput:

$= \frac{L}{RTT}$

If they are wrong please provide correct ones.

Comments

When do we use $\eta = 1/(1+6.44a)$ and when do we use $\eta = 1/(1+2a)$ {a = pd/td}. I am very confused between efficiency, throughput, utilization...please help!

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1 / (1 + 5.44 a) : This is correct. Follow it if the efficiency of Ethernet LAN is needed otherwise for sliding window or stop-and-wait use W / ( 1 + 2a) or 1/(1 + 2a).

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Thanks!