Here is a Visual Basic for Application (Microsoft Excel) function to calculate the payback time in years.
Function PayBack(Rango As Range, Optional Inversion As Double = 0, Optional Tasa As Double = 0) As Double
‘This is a Visual Basic for Application (Microsoft Excel) function to calculate the payback time in years.
‘The result is in years.
‘The parameters are:
‘Rango: the cash flow to analyze
‘Inversion: is the year where the investment ends.
‘This is an optional parameter for cash flows
‘where the initial down payment is in the firsts years
‘and make some year cash flow positive in excess
‘before the payback is done.
‘Tasa: here goes a rate to discount the cash flow.
‘This is an optional parameter.
‘
‘Copyright: pepemosca
’2007-04-26
Dim SumaParcial, Siguente, CantidadAnos As Double
SumaParcial = 0
Siguente = 0
CantidadAnos = 0
For Each Celda In Rango
SumaParcial = SumaParcial + Celda.Value / (1 + Tasa) ^ CantidadAnos
If SumaParcial >= 0 And CantidadAnos >= Inversion Then
Siguiente = Celda.Value / (1 + Tasa) ^ CantidadAnos
Exit For
End If
CantidadAnos = CantidadAnos + 1
Next Celda
PayBack = CantidadAnos – (SumaParcial – Siguiente) / Siguiente
End Function
The hot-stuff ATI Radeon HD 2900 XT graphics card is getting closer to its May ship date, and early benchmarks show it slam-dunking its primary competitor, NVIDIA’s GeForce 8800 GTS. This is ATI’s first DirectX 10-compatible card (new in Windows Vista), finally catching up to NVIDIA’s GeForce 8800 DirectX 10 cards. This combo of software and hardware will make gaming graphics run a whole lot faster, and gamers are also salivating over the card’s ability to scale up and run even faster at resolutions of 1920×1200 and beyond.
However, the benchmarks run by Daily Tech were at 1280×1024, because that was the only size monitor these guys had available when they did their hands-on testing. That said, the ATI Radeon HD 2900 XT handily beat the NVIDIA GeForce 8800 GTS 640MB card in every single benchmark, and some of the margins had the ATI card running more than 20% faster. Jump for another pic, plus pricing and a link to the benchmarks.
This is astonishing performance for a graphics card that will probably cost around $450. Plus, these cards are so pretty, you’re going to have to have a transparent case to fully enjoy their fire-breathing glory.
ATI Radeon HD 2900 XT Performance Benchmarks [Daily Tech]
The man at One Man’s Blog explains how alarmingly easy it is to crack passwords and offers tips on choosing safer ones.
First, he breaks down the steps he’d take in cracking a password. That includes the simple act of guessing the top ten passwords (pet’s name, “1234,” date of birth, etc.) used by 20 percent of all users. If that doesn’t work, he’ll turn to a brute-force attack, which, as you can see in the table above, can get the job done in as little as 0.02 seconds.
This is eye-opening stuff, even for users who know better than to use “1234″ as their password. Thankfully, the author goes on to provide seven great tips on choosing safer passwords, including using Microsoft’s password strength tester. Required reading. When you’re done, check out our other posts on smart password selection.
How I’d Crack Your Weak Passwords [One Man's Blog]
