SYD(cost, salvage, life, period)

Returns the sum-of-years' digits depreciation of an asset (Double).

cost	The initial cost of the asset (Double).
salvage	The value at the end of the depreciation (Double).
life	The length of the useful life of the asset (Double).
period	The period you want to calculate the depreciation over (Double).

REMARKS

* The "life" and "period" arguments must be expressed in the same units.
* You can use the DDB function to return the depreciation of an asset in a single period (double or triple declining balance method).
* You can use the SLN function to return the straight-line depreciation of an asset over a single period of time.
* The equivalent Excel function is Application.WorksheetFunction.SYD
* The equivalent .NET function is Microsoft.VisualBasic.Financial.SYD
* For the Microsoft documentation refer to docs.microsoft.com

Debug.Print Syd(500, 0, 1, 1)    '=  500  

Debug.Print Syd(500, 0, 2, 1)    '=  333.334  
Debug.Print Syd(500, 0, 2, 2)    '=  166.667  

Debug.Print Syd(500, 0, 3, 1)    '=  250  
Debug.Print Syd(500, 0, 3, 2)    '=  166.667  
Debug.Print Syd(500, 0, 3, 3)    '=  83.333  

Debug.Print Syd(10000, 9000, 1, 1)    '=  1000  
Debug.Print Syd(10000, 9000, 2, 1)    '=  666.667  
Debug.Print Syd(10000, 9000, 3, 1)    '=  500  
Debug.Print Syd(10000, 9000, 10, 1)   '=  181.818  

Debug.Print Syd(30000, 7500, 10, 1)   '=  4090.909  
Debug.Print Syd(30000, 7500, 10, 10)  '=  409.091  

Debug.Print Syd(10000, 500, 24, 12)   '=  411.667  

Debug.Print Syd(10000, 9000, 1, 2)    'Run-time error 5  
Debug.Print Syd(10000, 9000, 3, 10)   'Run-time error 5  
Debug.Print Syd(10000, 500, 3, 10)    'Run-time error 5