Returns the depreciation of an asset for a specified period using the fixed-declining balance method.
The initial cost of the asset.
The value at the end of the depreciation (sometimes called the salvage value of the asset).
The number of periods over which the asset is being depreciated (sometimes called the useful life of the asset).
The period for which you want to calculate the depreciation. Period must use the same units as life.
The number of months in the first year. If omitted, it is assumed to be 12.
Contributors: Alberto Ferrari, Marco Russo