Question

When n = energy efficiency and Pin = energy input and Pout = energy output, how can you mathematically represent the correct relationship between the energy you put in something and the energy you get out?

Answer 1

various ways, however I would make the energy efficiency a percentage. So the energy output divided by the input. (this will always be less than 1, do you know why?)

Answer 2

I would say:\[n=\frac{ P _{i n}-P _{out} }{ P _{ i n} }\]Therefore:\[P _{out}=P _{i n}- nP _{i n}\]