## Sunday, January 31, 2016

### Video: Dot vs Cross Product

Dot vs Cross Product Video:

Eddie

## Tuesday, January 26, 2016

### Video: The F.O.I.L. Technique in Algebra

The F.O.I.L. Technique in Algebra

An efficient way of multiplying two binomials (x + y)*(a + b)

Eddie

## Monday, January 25, 2016

### Video: Combinations vs Permutations

This short video explains the difference between combinations and permutations.

Eddie

### Change of Plans

Apparently, someone on YouTube, maybe the company itself, doesn't like algebra. Who knew talking about the F.O.I.L. method was so offensive? I am appealing the decision.

For the time being, I will probably cease making videos until this matter is resolved (I expect it to be in my favor, but who knows).

Eddie

Update: YouTube restored my FOIL video and I am back in good standing.  Happy dance!  Eddie

## Sunday, January 24, 2016

### Math Videos and Update

 Sample Slide

Over the next few weeks I am going to working several short math videos that I will post on YouTube.  When each video is completed, I will leave a link to that video on this blog.

The videos are going to be pretty short covering various topics in mathematics.

I hope you enjoyed the HP 15C programs posted over the last two weeks.  I plan to continue to post programs for various calculators this year.

I thank you for the comments and reviews.  Talk to you next time, and be safe everyone,

Eddie

## Thursday, January 14, 2016

### HP 15C: Approximate Length of Sunlight During a Day

HP 15C:  Approximate Length of Sunlight During a Day

Source: Total Daily Amount of Solar Radiation - HP 67/97 Energy Conservation Pac, December 1978, Author: Hewlett Packard

Instructions:

Y Stack:  Enter the latitude (North as positive, South as negative).  Use the D.MMSS (degrees-minutes-seconds) format

X Stack:  The number of days after March 21.  A 365 day year is assumed, as well as assuming March 21 is the vernal equinox.

Run the program.

This is an approximation.

Program:

 Step Key Key Code 001 LBL E 42, 21, 5 002 DEG 43, 7 003 . 48 004 9 9 005 8 8 006 5 5 007 6 6 008 * 20 009 SIN 23 010 2 2 011 3 3 012 . 48 013 4 4 014 5 5 015 * 20 016 X<>Y 34 017 >H 43, 2 018 TAN 25 019 X<>Y 34 020 TAN 25 021 CHS 16 022 * 20 023 COS^-1  (ACOS) 43, 32 024 >RAD 42, 3 025 2 2 026 4 4 027 * 20 028 Ï€ 43, 26 029 ÷ 10 030 >H.MS 42, 2 031 RTN 43, 32

Example:

Los Angeles, April 17.  Latitude of 34°03’ N, 27 days after March 21.
Result:  approximately 12.5735 (12 hours, 57 minutes, 35 seconds)

Sydney, June 21.  Latitude of 33°51’31” S (enter as -33.5131), 92 days after March 21.
Result:  approximately 9.4439 (9 hours, 44 minutes, 39 seconds)

Rome, September 1.  Latitude of 41°51’ N, 164 days after March 21.
Result:  approximately 12.5323 (12 hours, 53 minutes, 23 seconds)

This blog is property of Edward Shore.  2016

### HP 15C: Soderberg’s Equation for Fatigue

HP 15C: Soderberg’s Equation for Fatigue

Source:  Step by Step Solutions for your HP Calculator: Engineering Applications.  HP-32S.  Hewlett Packard.  Corvallis, OR.  1988  pg. 52-54

Equation:

Syp/FS = (Smax + Smin)/2 + K * (Syp/Se) * ((Smax – Smin)/2)

Variables:

R0 = Syp = yield point stress
R1 = Se = endurance stress reversed bending tests
R2 = Smax = maximum applied stress
R3 = Smin = minimum applied stress
R4 = K = stress concentration factor
R5 = FS = factor of safety

Instructions:

Enter the known values in each of the variables.  Enter the number of the variable to be solved in register I ( [ STO ] [ TAN ] (I) ).  To solve, enter a range, and press [ f ] [ ÷ ] (SOLVE), [ e^x ] (B). (*or whatever label you assigned this program to)

Program:

 Step Key Key Code 001 LBL B 42, 21, 12 002 STO (i) 44, 24 003 RCL 0 45, 0 004 RCL÷ 5 45, 10, 5 005 RCL 2 45, 2 006 RCL+ 3 45, 40, 3 007 2 2 008 ÷ 10 009 - 30 010 RCL 2 45, 2 011 RCL- 3 45, 30, 3 012 2 2 013 ÷ 10 014 RCL* 0 45, 20, 0 015 RCL÷ 1 45, 10, 1 016 RCL* 4 45, 20, 4 017 - 30 018 RTN 43, 32

Example:

Find the yield point (R0) given the following:
R1 = Se = 33,000 psi
R2 = Smax = 20,000 psi
R3 = Smin = 10,000 psi
R4 = K = 1.5
R5 = FS = 2
Store 0 in RI.

Solution:  55,000 psi

This blog is property of Edward Shore.  2016

### HP 71B: Basic Expanded RPN Program (RPNT)

HP 71B: Basic Expanded RPN Program ( RPNT ) Introduction This program is an expansion of RPNBASIC that was posted on May 12, 2024....