Change of demand that occurs due to change in price of
substitutes or complements.
(QuantityA - QuantityB) / (QuantityA + QuantityB)
all divided by
(PriceA - PriceB) / (PriceA + PriceB)
As the price one good increases, the demand for an
alternative good meeting the same consumer needs, increases.
A good for which the demand increases as the price of an
associated good decreases.