HP 48G: Business Applications

 HP 48G:  Business Applications

Calculators Featured:  HP 48G, HP 48G+, HP 48GX

Percent Addition 

HP 48G Program: %PLUS

<< OVER SWAP % + >>

Stack:

2:  amount

1:  percent

Example 1:   150 + 17%

150 [ ENTER ] 17 (%PLUS) 

Result:  175.5

To subtract, make the percent negative.

Example 2:  170 - 18%

180 [ ENTER ] 18 [ +/- ] (%PLUS)

Result:  139.4

Interest Rate Conversion to APR

The program →APR converts a nominal interest rate (NOM) to the effective interest rate (APR/EFF) given the rate and the compound periods per year.

HP 48G Program:  →APR

<< "→APR"

{ { "I%YR:" } { "PYR:" } }

{ } { } { }

IF INFORM 

THEN OBJ→ DROP

SWAP 1 % OVER / 1 +

SWAP ^ 1 -  100 * 

"APR" →TAG END >>

Example   

nominal rate: 7.5%, periods per year: 6

Result:  

APR: 7.738318055 (%)

Source:

Thomsett, Michael C.  The Real Estate Investor's Pocket Calculator 2nd Ed.  American Management Association: New York.  2017

Present Value of a Growing Payment

The program PVGROW calculates the present value of a growing annuity.   Each payment grows by the rate g% while the discount rate is r%.

PV_grow = PMT_base / (R% - G%) * (1 - (1 +G%) / (1 + R%) ^ n )

HP 48G Program:  PVGROW

<< "PV GROWING ANNUITY"

{ { "1st Pmt:" } { "I/YR:" } { "Growth Rate:" } { "N: "} }

{ } { } { } 

IF INFORM

THEN OBJ→ DROP 4

ROLLD 1 % SWAP 1 %

SWAP - LASTARG 1 + 

SWAP 1 + / 4 ROLL 6

1 SWAP - 3 ROLLD /

* "PV" →TAG END >>

Example

1ST PMT:  1000.00

I/YR:  3.5 (%)

GROWTH RATE:  4 (%)

N: 36

Result:  

PV:  37890.784118

Source:

"Present Value of a Growing Annuity" financeformulas.net  https://financeformulas.net/Present_Value_of_Growing_Annuity.html   Retrieved December 13, 2020.  

Interest Only Loan

The program INTONLY calculates payments from:

Interest-only payment

Payment (P&I) when the principal starts being due

HP 48G Program:  INTONLY

<< "INTEREST ONLY"

{ { "LOAN:" } { "I/YR:" } { "INT YRS:" } { "MAIN YRS:" } }

{ } { } { }

IF INFORM 

THEN OBJ→ DROP 12

* 'N' STO ROT DUP

'PV' STO ROT DUP

'I%YR' STO 1 % * 12

/ NEG 'IMPT' DUP2 

STO →TAG SWAP DROP

0 'FV' STO 12 'PYR'

STO 'PMT' TVMROOT

'PMT' →TAG END >>

Example

LOAN:  185000.00

I/YR:   4.55 (%)

INT YRS:  5

MAIN YRS: 30

Results:

IMPT: -701.4583333333   ($701.46 each month for the first 5 years)

PMT: -942.871969103   ($942.87 each month for the rest of the 30 years)

Source:

Kapfidze, Tendayi  "What Is an Interest-Only Mortgage and How Does It Work?"  Edited by Deborah Kearns  LendingTree.  LendingTree, LLC, Charlotte, NC:  2021.   https://www.lendingtree.com/home/mortgage/interest-only-mortgages/  Retrieved March 9, 2021

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Review: Calculated Industries ConcreteCalc Pro (4225)

Review:  Calculated Industries ConcreteCalc Pro (4225)

Quick Facts

Model Number:  4225

Company:  Calculated Industries

Year of Production:  2010 - present

Operating System:  Chain

Batteries: 1 x CR 2016

Memory Register:  1 independent (M), memories M1 - M3

Paperless Tape:  20 steps, arithmetic functions are recorded

Cost:  Retail:  $74.95, but selling prices vary.  I purchased mine used for $30 on eBay.

Product Page:

https://www.calculated.com/mobile/prd104/ConcreteCalc-Pro-4225-Concrete-Calculator.html

Consistent my recent reviews of Calculated Industries calculators, including the Pipe Trades Pro and the ElectricCalc Pro, I am impressed by the keyboard and the feel of the keys, love the Armadillo Gear case cover, and the calculator serves specific purpose and industry.  

Highlighted Features

Here are some, just some, of the features of ConcreteCalc Pro:  

Dimensional Math:  Calculations and conversions with units, both US and Metric, are available on the ConcreteCalc Pro.

Areas and Volumes:   The [ Length ], [ Width ], and [ Height ] keys serve as the entry keys to calculate area and volume.  

VOL = volume of the room

WALL = area of the one of the four walls

ROOM = total surface area of the walls

The results are accessed through repeated presses of the [ Height ] key.  

Geometry:  The ConcreteCalc Pro also works with calculating areas and circumferences of circles, volumes of cylinders and cones, and arc lengths.  Regular polygons are also included.  

Example:  6-sided polygon with radius of 5 in.  

5 [ Inch ] [ Conv ] [ Arc ] (Radius)

6 [ Conv ] [ Length ] (Polygon)

FULL:  120.00°

HALF:  60.00°

SIDE:  6

PER:  30 in (perimeter)

AREA:  64.95191 in^2  (area)

Loads, Blocks, Bags:  Calculate loads and bags of concrete based on volume, and the number of blocks based on area and the size of the blocks.

Stairs:  Use the [ Height ] key to store the total floor-to-floor rise, desired riser height, floor height, and tread width and you can get the run, incline of the stairs, the length of the stringer and more with the [ Stair ] key.  With the Riser Limited option, we can calculate these statistics restricting the desired the riser height as the maximum.  

Rebar calculations 

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Calculated Industries Qualifier Plus IIX and HP 12C: Maximum Loan Amount and Allowable Payment

Calculated Industries Qualifier Plus IIX and HP 12C:  Maximum Loan Amount and Allowable Payment

Introduction

Given the following:

*  term of the loan, in years

*  the amount mortgage

*  annual interest rate

*  monthly expenses including property tax and mortgage interest

The following are calculated:

*  payment, including PITI

*  minimum required income

*  maximum allowable (other) debt

Assumptions:

*  The standard 28:36 ratio is used (28% for PITI, 36% for PITI and other monthly debts)

*  Payments are made at the end of each month

Both of the above parameters are can be changed but the program uses these assumptions.

Formulas (as determined by verifying examples):

PITI =  PMT + monthly property insurance + monthly property tax

Minimum Required Income:

RI = (PITI * 12) / 0.28 

Maximum Allowable (Other Debt): (uses RI from Required Income)

MA = (RI * 0.36) / 12 - PITI

Calculated Industries Qualifier Plus IIx:  Key Strokes

Note:  The IIx is a predecessor of the Qualifier Plus IIIx, however I believe the key strokes should be the same.  

Inputs:

annual interest [ Int ]

number of years [ Term ]

amount to be financed [ L/A ]   ([Loan Amt] on the IIIx)

annual property tax [ Tax ]

annual property insurance [ Ins ]

Alternate to amount to be financed:

total price [ Price ],  down payment as a percent of the price [ Dn Pmt ]

Output:

[ Pmt ] to display payment

[ Pmt ] again to display PITI

[ Qual 1 ] to display the required minimum income

[ Qual 1 ] again to display the maximum allowable (other) debt

HP 12C: Program

Input Instructions: 

annual interest [ g ] (12÷)

number of years [ g ] (12×)

amount to be financed [ PV ]   

0 [ FV ]

monthly combined property tax and insurance [ R/S ]

Alternate:  

annual property tax [ ENTER ] annual property insurance [ + ] 12 [ ÷ ] [ R/S ]

Output:

to display payment

[ R/S ] again to display PITI

[ R/S ] again to display the required minimum income

[ R/S ] again to display the maximum allowable (other) debt

Step # :  Key Code:  Key

01 : 44,0         :    STO 0

02 : 14         :        PMT

03 : 14         :        PMT

04 : 31         :        R/S

05 : 45, 0 : RCL 0

06 : 16         : CHS

07 : 40         : +

08 : 44, 1 : STO 1

09 : 31         : R/S

10 : 48         : .

11 : 2         : 2

12 : 8         : 8

13 : 10         : ÷

14 : 44,3         : STO 3

15 : 1         : 1

16 : 2         : 2

17 : 16         : CHS

18 : 20         : ×

19 : 44,2         : STO 2

20 : 31         : R/S

21 : 45,3         : RCL 3

22 : 16         : CHS

23 : 3         : 3

24 : 6         : 6

25 : 25         : %

26 : 45,1         : RCL 1

27 : 40         : +

28 : 44,3         : STO 3

29 : 43,33,00 : GTO 00

Examples

Example 1:

annual interest:  4.7%

number of years: 30

amount to be financed:  305,000.00

annual property tax: 0.00

annual property insurance: 0.00

Results:

payment:  1,581.85

PITI:  1,581.85

required minimum income:  67,793.37

maximum allowable (other) debt: 451.96

Example 2:

annual interest:  5%

number of years: 30

amount to be financed:  235,000.00

annual property tax: 1,000.00

annual property insurance: 105.00

(monthly combined tax and insurance:  92.08)

Results:

payment:  1,261.53

PITI:  1,353.61

required minimum income:  58,012.03

maximum allowable (other) debt: 386.75

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

HP 48G: Scientific Applications

HP 48G:   Scientific Applications

Calculators Featured:  HP 48G, HP 48G+, HP 48GX

Theoretic Freezing Level

The program FRZLVL calculates the theoretical freezing level in feet above sea level given the outside temperature at a given altitude.  The results are displayed in feet (the feet unit is attached).  

HP 48G Program: FRZLVL

<< "FREEZING LEVEL"

{ { "ALT:" "DEFAULT FT" }

{ "TEMP:" "DEFAULT °C" } }

{ }  { }  { }  

IF INFORM

THEN OBJ→ DROP DUP TYPE

IF 13 == THEN '1_°C' CONVERT

ELSE '1_°C' →UNIT 

END SWAP DUP TYPE 

IF 13 == THEN '1_ft' CONVERT

ELSE '1_ft' →UNIT

END SWAP '1000_ft/°C' 

* DUP2 2 / +

"DRY" →TAG 3 ROLLD

1.5 / + "WET" →TAG END >>

Instructions

1.  Run FRZLVL

2.  ALT:  Enter altitude.  You can attach units if you want, the default is altitude is in feet.

3.  TEMP:  Enter outside air temperature.  You can attach units if you want, the default unit is degrees Celsius (°C).

4.  Results: freezing dry level in feet and freezing wet level in feet.  

Example

Altitude:  1,750 ft

Temperature:  -2°C  (28.4°F)

Results:

DRY:  750_ft

WET:  416.666666667_ft

Source:

Hewlett Packard  "Predicting Freezing Levels" HP 65 Aviation Pac 1.  Hewlett Packard.  1974

Lens Calculations 

Variables

Please note the inequality restrictions.  

R = radius of curvature

D = diameter of the lens, D ≤ 2*R

S = sag S ≤ R

θ =  tangent angle between lens axis and reflection 

HP 48G Program: LENSANG

<< 'R=(D^2+4*S^2)/(8*S)' STEQ

{ { "R/D" << 'D' STO 'R' STO EQ  'S' 0 ROOT 'S' →TAG >> } 

{ "R/S" << 'S' STO 'R' STO EQ 'D' 0 ROOT 'D' →TAG >> }

{ "D/S" << 'S' STO 'D' STO EQ 'R' 0 ROOT 'R' →TAG >> } 

{ "→θ" << 'D' RCL 'R' RCL 'S' RCL - 2 * / ATAN 'θ' DUP2 STO →TAG >> } }

TMENU >> 

Instructions

1.  Run LENSANG.  A temporary custom menu appears.  

2.  Enter two known amounts and press the appropriate key to store the variables:

If R and D are known:  R [ ENTER ] D [ F1 ] 

If R and S are known:  R [ ENTER ] S [ F2 ]

If D and S are known:  D [ ENTER ] S [ F3 ]

The third variable between R, D, and S is calculated and displayed as a result.

3.  Press [ F4 ] to calculate the angle, θ.  

Results are stored in the variables R, S, D, and θ.

Examples

Known:  R = 5.8, D = 7.6

LENSANG  5.8 [ ENTER ] 7.6  [ F1 ] (R/D)

Result:  S: 1.41821953996

[ F4 ] (θ).  Result:  θ:  40.9327245742

Known:  D = 11, S = 9

LENSANG 11 [ ENTER ] 9 [ F3 ] (D/S)

Result:  R: 6.18055555556

[ F4 ] (θ).  Result:  θ:  -62.8591312297

Source:

Tuchscherer, L.D.  "Lens Calculations - SAG, ANGLE, MIN/MAX" HP 67 Optics  Hewlett Packard.  1978.

Period of a Pendulum

The program PENDULUM calculates the period of a pendulum given two parameters:

ANGLE: the angle that the pendulum swings out.  The angle must be entered in radians.

LENGTH:  The length of the pendulum in meters. 

Unlike most calculations, the program uses an Legendre elliptic integral of the first kind to increase accuracy.  

T = 4 * √(L / g) * ∫( dx / √(1 - k^2 * sin^ x), x, 0, π/2) where k = sin(α/2)

g = Earth's gravitational constant = 9.80665 m/s^2

This program does not use units.  

HP 48G Program: PENDULUM

<< RAD 

"PENDULUM"

{ { "ANGLE:" "IN RADIANS" }

{ "LENGTH:" "IN METRES" } }

{ } { } { } 

IF INFORM

THEN OBJ→ DROP

9.80665 / √ 4 *

SWAP 2 / SIN SQ 0 θ π 2 /

→NUM 3 ROLL 'X' 

SIN SQ * 1 SWAP - √

INV 'X' ∫ →NUM *  

"PERIOD" →TAG END >>

Example

ANGLE:  π/6   (enter this as 'π/6')

LENGTH: 1.5  (m)

Result:  

PERIOD:  2.50011881685 (s)

Source:

Steers, Hugh.  "The Pit & Pendulum"  Datafile.  ISSN 1352-8254.  Handheld and Portable Computer Club.   V29 N1.  January - March 2010

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Calculos: Mathematics Calculation Game (Kickstarter)

Calculos:  Mathematics Calculation Game  (Kickstarter)

The Card Game

Xavier Wilain created the card game Calculos, which is based on quick, mental mathematics dealing with the four arithmetic operations:  addition, subtraction, multiplication, and division.  There is a mixed version that has all four arithmetic operations.  

Players start with a card and try to find a calculation that matches any of the calculations on the center card.  

For example, if the center card has:

2 × 5

3 × 6

5 × 5

4 × 4

If you have any of the calculations on your card, say 4 × 4, you shout "4 times 4 equals 16" and claim the card.  The object is for find a calculation faster than their opponents.   

Here is a video of the card game and how to play it:

https://www.youtube.com/watch?v=-PEfEVTV4wI

The card game comes in four levels: each level has a different set of calculations on the card, from four to eight.   On the XW_SeriousGames website, each level can be purchased separately or altogether for each operation.

Link:  https://www.xwseriousgames.com/

The Mobile App (Kickstarter)

Wilain is running a Kickstarter campaign to adapt the card game into a mobile app that contains all 20 levels (4 four levels for each arithmetic operation plus one for mixed) with plans to add levels in the future.  Wilain has goal to raise 33'000 CHF (Swiss Francs, which is $35,897.63 in US Dollars on 6/28/2021 - conversion provided by Morningstar).  If successful, the mobile app is set to begin development in October 2021.  The target fund date is July 27, 2021.  

Kickstarter page:

https://www.kickstarter.com/projects/xw-serious-games/calculos/description

Please check this game out, it promises to be a great way to strength our mental calculation skills.  

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Review: Calculated Industries ElectricCalc Pro (Model 5070)

Review:  Calculated Industries ElectricCalc Pro (Model 5070)

Quick Facts

Model Number:  5070

Company:  Calculated Industries

Year of Production:  2014 - present

Operating System:  Chain

Batteries: 1 x CR 2016

Memory Register:  1 independent (M), memories M1 - M9

Upgradable Chip:  Base Model is set for 2014, chips are available for 2017 and 2020 (and I presume 2023 given how often NEC updates their code)

Cost:  Retail:  $99.95, but sells for anywhere from $59 to as high as $129.  Do your shopping carefully!  

Product Page:  https://www.calculated.com/mobile/prd160/ElectriCalc-Pro-5070-Electrical-Code-Calculator.html

Make Sure Your ElectricCalc Is Up to Code 

Bought new or in box, the calculator comes in a blue Armadillo Gear case.  Often, the ElectricCalc Pro comes with the latest chip (2020) already installed or in my case, my calculator had the 2017 chip installed and the 2020 chip in a separate package.   Installation is simple and you just need a Phillips screwdriver.  

Currently, the ElectricCalc handles code for the following years:

1996

1999

2002

2005

2008

2011

2014

2017 (2017 or 2020 chip required)

2020 (2020 chip required)

Set your jurisdiction by pressing [ Set ] [ ÷ ].  The first preference is the NEC, which you can scroll by pressing [ + ] and [ - ].

Many calculations depend on the NEC code such as wire size, voltage drop, ground conductor wire size, and conduit sizes for wires.   Many of the calculations display the reference table.   Because of the stored values for the NEC codes, the ElectricPro already proves its value.  

Wire Insulation can be selected:

[ Set ] [ 7 ]:  75°C wire insulation (167°F)

[ Set ] [ 9 ]:  90°C wire insulation (194°F)

[ Set ] [ 6 ]:  60°C wire insulation (140°F)

We can work with copper and aluminum wires with the [ Set ] [ 4 ] toggle.   

Ohm's and Kirchhoff's Law

The ElectricCalc Pro has the following keys to work with Ohm's Law:

[ Set ] [ V ] ( R ):  Resistance in Ohms (Ω)

[ Set ] [ Volts ] (Vdc):  Voltage in Volts (V)

[ Set ] [ Amps ] (Idc):  Current in Amps (A)

Likewise, the keys work with Kirchhoff's Law:

[ VA ]:  Volt-Amps

[ Volts ]:  Voltage in Volts (V)

[ Amps ]:  Current in Amps (A)

1 Phase vs 3 Phase

Select 1 Phase mode by pressing [ Set ] [ 1 ].  For 3 Phase, press [ Set ] [ 3 ].   

What is great about the ElectricCalc Pro, the settings will be displayed at all times.  

Verdict

The keyboard of the ElectricCalc Pro work well and the keys give good feedback.  Like the other Calculated Industries calculators, the calculators hold data specific to the industry.  

And like the Calculated Industries calculators, having the ElectricCalc Pro opens up a new world of knowledge.   I'm glad to have the calculators in my collection.  

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Review: Victor 6500 Loan Calculator, HP 48G Retro Month

Review:  Victor 6500 Loan Calculator, HP 48G Retro Month

Victor 6500 Review

Quick Facts

Company:  Victor

Year Introduced:  about 2010, still in production

Battery:  Solar and 1 AA battery

Digits: 12

Memory Registers:  2: Independent (M) and Grand Total (GM)

Cost: About $20.00 to $25.00 US

Product Page:  https://www.victortech.com/product/6500

It is rare that a desktop calculator features advanced financial or scientific functions, and that is what attracted me to the Victor 6500.  The keys respond quickly which allows for fast typing.   The display has room for 12 large digits which makes reading the display easy.

Features

*  Fix Display Switch: Float, 0, 2, 4, Add Mode

*  Round Setting Switch:  cut (always round results down), 5/4 (regular rounding rules are followed), up (always round up)

*  Time Value of Money - will be discussed next

*  %, Δ%, √

*  Tax Rate:  setting, TAX+, TAX-

*  Double Zero Key

Memory Registers

There are two memory registers:

Independent Memory (M).  This the traditional memory register that comes with most desktop calculators.  Included are M+ and M-.  Recall and clear are combined in one key RCM.

Grand Total (GT).  The grand total memory is activated every time the equals key is pressed.   

Time Value of Money

The Victor 6500 have four finance keys:

Loan = PV

Pmt = Payment

Years = number of years = n * PYR

Int = annual interest rate

The cash flow convention (inflow/outflow) is not followed, all results are positive.  The number of payments per year is set through the P/Y setting.  

What is missing is the FV (future value) key, which leaves out some of the finance problems involving calculating balance or balloon payment.   However, we can still do a lot of calculations on the Victor 6500 fairly easier.  Here are several example calculations.  In these examples, the Victor 6500 is set to 2 Decimal Places with 5/4 rounding mode.

Example 1:  Calculating Payment of a Loan

Loan:  345,000.00

Years: 30

Interest Rate:  3.3%

[ ON/C ] [ ON/C ]

345000 [ Loan ]

30 [ Years ] 

3.3 [ Int ]

[ Pmt ]  returns 1,510.95

Example 2:  Calculating Payment of a Loan with a Down Payment

Loan:  260,000.00 with 15% down

Years: 27

Interest Rate:  3.2%

[ ON/C ] [ ON/C ]

260000 [ - ] 15 [ % ] [ Loan ]

27 [ Years ] 

3.2 [ Int ]

[ Pmt ]  returns 1,019.53

Example 3:  PITI (Payment with Principal Interest Taxes Insurance)

Loan: 300,000.00

Years: 30

Interest Rate: 3.25%

Annual Property Tax: 2,121.00

Annual Property Insurance: 541.00

[ ON/C ] [ ON/C ] [ MRC ] [ MRC ]

300000 [ Loan ]

30 [ Years ]

3.25 [ Int ] 

[ Pmt ] [ M+ ]

2121 [ + ] 541 [ = ] [ ÷ ] 12 [ = ] [ M+ ]

[ MRC ] (once)  

PITI:  1527.45

Verdict

I like the Victor 6500 since it offers a time value of money solver on a desktop calculator form.  I wish Victor would have included the future value variable.   The keys are fast and responsive.  The keyboard is pretty light but also feel stable.  

I am working on posting additional examples for the Victor 6500 in the near future.  

HP 48G Retro Month - July 2021

For the month of July 2021, every Saturday from July 10 to July 31 will have a post on the legendary HP 48G/48GX/48G+ calculator.  

Next post will be on July 10, 2021 (taking the Fourth of July weekend off).   Have a great day and thank you!  

Eddie 

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

7000G Retro Month - June 26 Edition

7000G Retro Month - June 26 Edition

Introduction

Welcome to the 7000G Retro Month, which features programming for the classic Casio calculators from the mid/late 1980s:  primarily fx-7000G and fx-7500G.  Since the programming language stays similar throughout the years, programs can be translated to the fx-6300G and later graphing calculators with little to no adjustments.  Non graphic programs should be ported to the fx-4000P, fx-4500P (A), fx-3650p (II), fx-50F Plus (II), and fx-5800P with little to no adjustments.  

7000G Retro Month takes place every Saturday during June 2021.

To make text easier to type, I can going to use the following text friendly symbols for the following:

->  for →

/I for ⊿

=> for ⇒

What do you think?   Unicode or simple text equivalents?  

- - - - - - -- - -- - -

Today's subject revolves around Calculus.  Enjoy!

- - - -- - - -- - -- -- -

The three programs listed here call another program as a subroutine.  I use Prog 0 as a subroutine.  

Prog 0 

[insert f(x) here]

Example:  Prog 0 contains X^2+4.   The results gets stored in in Ans.  

Sum

S = ∑( f(x), X = A to B)

"A"? -> A

"B"? -> B

A -> X

0 -> S

Lbl 1

Prog 0

Ans + S -> S

X + 1 -> X

X≤B => Goto 1

S

Numeric Derivative - Simple Approximation

f'(x) ≈ (f(x+h) - f(x-h))/(2h),  h = tolerance (default to 10^-5)

The derivative is stored in the variable D. 

"X0"? -> Z

Z+10^-5 -> X : Prog 0 : Ans -> A

Z-10^-5 -> X : Prog 0 : Ans -> B

(A-B)÷(2 10^-5) -> D

Definite Integral - Simpson's Rule

∫ f(x) dx ≈ h/3 * (y_a + ∑(4*y_odd + 2*y_even) + y_b)

where h=(b-a)/n   (n is even)

The integral is stored in the variable I.

"A"? -> A 

"B"? -> B

"N"? -> N

A -> X

Prog 0

Ans -> I

(B-A)÷N -> D

N÷2 -> K

Lbl 2

X+D -> X : Prog 0 : I + 4 Ans -> I

X+D -> X : Prog 0 : I + 2 Ans -> I

K - 1-> K

K≠0 => Goto 2

B -> X : Prog 0 : (I - Ans)D÷3 -> I

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Update: HP Prime Connectivity Kit and Emulator

 Update: HP Prime Connectivity Kit and Emulator

The HP Prime Connectivity Kit and Emulator have been updated.  The version number is 14592 (6/9/2021).  Download them from this page:

https://www.hpcalc.org/prime/pc/

The 14588 (5/5/2021) firmware is still the current firmware for the HP Prime, which can be downloaded from the same page.

As a reminder, the newest firmware introduces, among other things, the Python app to the HP Prime.  Click on this link to read about some of the new features:  http://edspi31415.blogspot.com/2021/05/hp-prime-firmware-update-beta-python.html

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: Sharp EL-8131

Retro Review:  Sharp EL-8131

Many thanks to Christopher Brame for sending and giving me this calculator.  Thank you, my friend.

Quick Facts:

Company:  Sharp

Year Introduced:  1977, in production to 1978

Type:  Four Function

Batteries:  2 x AA batteries

Display:  8 digits

Background

The Sharp EL-8131 is a four function function from the 1970s with classic green digits in the display.  The calculator is nice and compact and held in one hand, while the other hand operates the well-designed keys.  

The functions of the EL-8131 include:

* Arithmetic

* Memory:  Store ( x→M), clear, recall, M-, M+

* Square Root

* Percent 

What is missing is the change sign key.  This presents a challenge when calculating with negative numbers.   

With any four function calculators, calculations are executed in the order you press the keys.  

Source:

"Sharp EL-8131 Handheld Electronic Calculator"  National American of American History.  Behring Center.  Washington, D.C.  https://americanhistory.si.edu/collections/search/object/nmah_334546  Retrieved May 23, 2021

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.