Result discrepancies with FINV function

[Stojko]

Hi,
I'm trying to use Excel's FinV function in two different ways. Each formula should generate the same answer but it does not.

For example:
Finv(0.055,1,8) should equal Finv(0.055,1,power(8*8*8,1/3)). When using Finv(0.055,1,power(8*8*8,1/3)) I get the "expected" result. However, when using Finv(0.055,1,8) I get an incorrect result. The "expected" result can also be obtained from a textbook look-up table (this is where I go to double-check my excel calculation).

There seems to be no fundamental difference in these two formulas. Can someone explain why these two results are not the same? Also, why doesn't Finv(0.055,1,8) result match the look-up table while the other formula does match (gets very, very close).

I plan on using the formula containing the power function but nevertheless am concerned why such a variation in results.

Thank you.

 

[Norie]

Perhaps it's something to do with the floating point errors that are intrinsic to most computers - nothing to do with Excel really.