01-05-2014, 01:06 AM

EDIT: The following listing has been edited to reflect feedback from forum members and match the listing in the software library here.

This is (was) my first post on the 'new' forum.

I am trying to adapt the Accurate TVM routine for Pioneers to the HP-15C using Karl Schneider's technique for invoking SOLVE with the routine written as a MISO (multiple-input, single-output) function, with indirect addressing. In this case, there are 6 variables (5 knowns). Karl's article can be found here.

Unfortunately I cannot get it to work and I have exhausted my non-programmer's efforts to debug!

My HP-15C adaptation of the code is as follows (apologies for the formatting):

001 f LBL E

002 STO(i)

003 RCL 2

004 EEX

005 2

006 ÷

007 ENTER

008 ENTER

009 1

010 +

011 LN

012 X<>Y

013 LSTx

014 1

015 X≠Y

016 -

017 ÷

018 *

019 RCL * 1

020 e^x

021 ENTER

022 RCL * 3

023 X<>Y

024 1

025 -

026 RCL * 4

027 EEX

028 2

029 RCL ÷ 2

030 RCL + 6

031 *

032 +

033 RCL + 5

034 RTN

When I try solving for the Present Value (or initial balance 'B') with the following values for a 4 year car loan, at 2.9% annual interest, and $ -658.39 monthly payment:

N = 48 STO 1

I = .2417 (2.9% annual) STO 2

B = STO 3 (in this case the variable I want to solve for, so 3 STO I)

P = -658.39 STO 4

F = 0 STO 5

E = 0 STO 6

The answer in register 3, should be B = 29,804.68. Instead I get B = -214,521.14

Can anyone help me troubleshoot this routine? If I can have a MISO solver routine for the TVM equation in my 15C, it will be very useful indeed. Can then leave the financial calc at home.

Regards,

Jeff Kearns (Ottawa)

This is (was) my first post on the 'new' forum.

I am trying to adapt the Accurate TVM routine for Pioneers to the HP-15C using Karl Schneider's technique for invoking SOLVE with the routine written as a MISO (multiple-input, single-output) function, with indirect addressing. In this case, there are 6 variables (5 knowns). Karl's article can be found here.

Unfortunately I cannot get it to work and I have exhausted my non-programmer's efforts to debug!

My HP-15C adaptation of the code is as follows (apologies for the formatting):

001 f LBL E

002 STO(i)

003 RCL 2

004 EEX

005 2

006 ÷

007 ENTER

008 ENTER

009 1

010 +

011 LN

012 X<>Y

013 LSTx

014 1

015 X≠Y

016 -

017 ÷

018 *

019 RCL * 1

020 e^x

021 ENTER

022 RCL * 3

023 X<>Y

024 1

025 -

026 RCL * 4

027 EEX

028 2

029 RCL ÷ 2

030 RCL + 6

031 *

032 +

033 RCL + 5

034 RTN

When I try solving for the Present Value (or initial balance 'B') with the following values for a 4 year car loan, at 2.9% annual interest, and $ -658.39 monthly payment:

N = 48 STO 1

I = .2417 (2.9% annual) STO 2

B = STO 3 (in this case the variable I want to solve for, so 3 STO I)

P = -658.39 STO 4

F = 0 STO 5

E = 0 STO 6

The answer in register 3, should be B = 29,804.68. Instead I get B = -214,521.14

Can anyone help me troubleshoot this routine? If I can have a MISO solver routine for the TVM equation in my 15C, it will be very useful indeed. Can then leave the financial calc at home.

Regards,

Jeff Kearns (Ottawa)