(17B/19B) GPM: initial payment

[Gil]

I think the only 5 important things to know all about the above are:

0) Yearly shown interest I%YR by the bank is useless for the calculations —> 1+effective%YR×100=r=(1+I%YR/100/P.YR)^P.YR
1) 4 % during 2 years —> r=(1+4/100)*(1+4/100)=1.04²
2) a=1+r+r²+r³ —> ar=r+r²+r³+r⁴ —> a=(r⁴-1)/(r-1),
with r=r (or r=v=1/r for discounting to the present)
3) For graduated case, instead of only r,
we have PMT× g, PMT ×g², g being of the form of r above
4) PMT at the beginning = (PMT calculated at end of period)/r

The remaining formulae are "dangerous" to apply without understanding the logic of the above.

Regards,
Gil