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Equation 2 · Part 1 · The Metabolism of Civilization: Energy to 2100

Symbol z

zz
zz

What this part means

z is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

z is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

The formal relationship goes back to Theodore Wright’s 1936 observation that aircraft manufacturing labor hours fell as a power-law function of the number of airframes already built, and Way et al. build their entire forecasting method on a stochastic version of it, fitted to more than fifty technologies’ historical cost and production records [ 1 ] . Written in its cleanest form, cost c at cumulative production (experience) z relates to a reference cost c0c_0 at reference experience z0z_0 by:

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A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the surrounding passage

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