how to use mort.raw?

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Walter
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Re: how to use mort.raw?

Post by Walter » Sun May 24, 2020 3:12 pm

HPMike wrote:
Sun May 24, 2020 1:53 pm
DHCrocks wrote:
Sun May 24, 2020 5:09 am
oh, what is DUE variable?
It is a setting to determine if payments are to be made at the end of a payment period (arrears), in which case DUE=0, or if they are made at the beginning of a payment period when due, in which case DUE=1. When payments are made when due, they are lower, since no interest will accrue during that period on the current unpaid balance. In this case, with DUE=0, then PMT=45.8037941842, whereas if DUE=1, then PMT=44.4697030914.
IMO, this DUE is an inartful term here since the payment is due anyway, either at beginning or end of each period. A variable called BEGIN would be more appropriate for what it does.
DM42 SN: 00041 Beta
WP 43S running on this device

HP-35, HP-45, ..., HP-50, WP 34S, WP 31S, DM16L

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PierreMengisen
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Re: how to use mort.raw?

Post by PierreMengisen » Sun May 24, 2020 3:44 pm

in French we talk about pre-numerando and post-numerando payment.
These are two modes of treatment. Why not talk about "KOP" (kind of payment)?
Pierre
[TI59 with PC100C; TI-84 Plus CE-T; HP41CV with HP IL loop & 2*82161A DCD & 82162 TP; HP15C; HP28S; DM41; DM41L; DM42; DM41X]

HPMike
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Re: how to use mort.raw?

Post by HPMike » Sun May 24, 2020 5:54 pm

Walter wrote:
Sun May 24, 2020 3:12 pm
HPMike wrote:
Sun May 24, 2020 1:53 pm
DHCrocks wrote:
Sun May 24, 2020 5:09 am
oh, what is DUE variable?
It is a setting to determine if payments are to be made at the end of a payment period (arrears), in which case DUE=0, or if they are made at the beginning of a payment period when due, in which case DUE=1. When payments are made when due, they are lower, since no interest will accrue during that period on the current unpaid balance. In this case, with DUE=0, then PMT=45.8037941842, whereas if DUE=1, then PMT=44.4697030914.
IMO, this DUE is an inartful term here since the payment is due anyway, either at beginning or end of each period. A variable called BEGIN would be more appropriate for what it does.
BEGIN is not a variable either, since it represents only one case for a binary choice. On my HP 12C, there are two choices, BEGIN for payments made at the beginning of a payment period, and END for payments made at the end of a period. So DUE in fact makes perfect sense for the variable, as it requests the answer to the question of when is the payment due for each payment period. Perhaps the variable name should be WD for “when due.”
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Walter
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Re: how to use mort.raw?

Post by Walter » Sun May 24, 2020 8:08 pm

HPMike wrote:
Sun May 24, 2020 5:54 pm
Walter wrote:
Sun May 24, 2020 3:12 pm
HPMike wrote:
Sun May 24, 2020 1:53 pm
It is a setting to determine if payments are to be made at the end of a payment period (arrears), in which case DUE=0, or if they are made at the beginning of a payment period when due, in which case DUE=1. When payments are made when due, they are lower, since no interest will accrue during that period on the current unpaid balance. In this case, with DUE=0, then PMT=45.8037941842, whereas if DUE=1, then PMT=44.4697030914.
IMO, this DUE is an inartful term here since the payment is due anyway, either at beginning or end of each period. A variable called BEGIN would be more appropriate for what it does.
BEGIN is not a variable either, since it represents only one case for a binary choice. On my HP 12C, there are two choices, BEGIN for payments made at the beginning of a payment period, and END for payments made at the end of a period. So DUE in fact makes perfect sense for the variable, as it requests the answer to the question of when is the payment due for each payment period. Perhaps the variable name should be WD for “when due.”
You're right in principle (a variable BEGIN presumes you know the only alternative is end - so if BEGIN = false then end must be true and vice versa). But a variable DUE or even WhenDue by its name asks for a date, or for an answer reading begin or end; none of these answers is true or false. So any intelligent compiler would throw a data type mismatch here.
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WP 43S running on this device

HP-35, HP-45, ..., HP-50, WP 34S, WP 31S, DM16L

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akaTB
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Re: how to use mort.raw?

Post by akaTB » Sun May 24, 2020 9:21 pm

Just to add a little more confusion: in italian DUE means TWO. ;)
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Geoff Quickfall
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Re: how to use mort.raw?

Post by Geoff Quickfall » Mon May 25, 2020 12:03 am

Due = two

Well that is too funny to!

DHCrocks
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Re: how to use mort.raw?

Post by DHCrocks » Mon May 25, 2020 6:25 am

so sorry but this is my first time using the DM42, I previously had various models of 48, so this it a bit different.

can some one walk me thru the steps? as an example, this is the loan I would like to calculate. $50,000 loan [pv], 60 months [60], 2.5% interest

this is what i'm doing
[xeq]
[mort]
0 [due]
0 [fv]
50,000 [pv]
0.025
60 [n]
[pmt][pmt]

the result is 1,617.67 which is obviously wrong it should be returning 887.37

thanks for the guidance.

DHCrocks
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Re: how to use mort.raw?

Post by DHCrocks » Mon May 25, 2020 8:46 am

I just got my DM42 and are not used to using it, I'm coming from using various HP48 for the past 20 years or so. Can someone please walk me thru the steps? I just cant seem to get it to work this is what I try:

[xeq]
[mort]
0 [due]
0 [fv]
50,000 [pv]
2.5
60 [n]
[pmt] [pmt]

result is 125,000 which is not correct it should be 887.37. this is for a 50,000 loan, 5 years, 2.5% interest.

thank you for the guidance and patients.

HPMike
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Re: how to use mort.raw?

Post by HPMike » Mon May 25, 2020 12:42 pm

DHCrocks wrote:
Mon May 25, 2020 6:25 am
so sorry but this is my first time using the DM42, I previously had various models of 48, so this it a bit different.

can some one walk me thru the steps? as an example, this is the loan I would like to calculate. $50,000 loan [pv], 60 months [60], 2.5% interest

this is what i'm doing
[xeq]
[mort]
0 [due]
0 [fv]
50,000 [pv]
0.025
60 [n]
[pmt][pmt]

the result is 1,617.67 which is obviously wrong it should be returning 887.37

thanks for the guidance.


You forgot to divide the annual interest by twelve to get monthly compounding interest. So, monthly interest = 0.025 / 12 = 0.00208333 will give you the result 887.3680803. Note that interest is entered as decimal value, not a percentage.
DM15L, S/N 00548. DM42, SN: 00159.

DHCrocks
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Joined: Fri May 22, 2020 11:09 pm

Re: how to use mort.raw?

Post by DHCrocks » Mon May 25, 2020 9:48 pm

HPMike wrote:
Mon May 25, 2020 12:42 pm

You forgot to divide the annual interest by twelve to get monthly compounding interest. So, monthly interest = 0.025 / 12 = 0.00208333 will give you the result 887.3680803. Note that interest is entered as decimal value, not a percentage.



That’s it! Thank you so much. That’s a strange way of inputting interest. I just hope I can remember it when I actually need to use the program a year from now. lol.

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