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Great entry Eddie! Love to see the 12c working in all sorts of areas.

Consider sharing on your blog some of the game programs for the 12c found here too.

12c document

More fun with the HP-12C: HP-12C’s Serendipitous Solver

Valentin doesn't even need to sign his work. Tanquam ex ungue leonem.

Here is part II:

http://edspi31415.blogspot.com/2014/10/m...error.html

Thank you so much guys! My next blog entry is a compilation featuring the three links suggested and two more: HP 12C Games and Black-Scholes.

Link: http://edspi31415.blogspot.com/2014/10/h...olver.html

Combining both of Valentin's ideas we can define the Taylor series of sin:

0 CF₀
1 CF_j
x<>y CF_j x<>y
2 CHS ÷ 3 ÷ CF_j
x<>y CF_j x<>y
4 CHS ÷ 5 ÷ CF_j
x<>y CF_j x<>y
6 CHS ÷ 7 ÷ CF_j
(...)
x<>y CF_j x<>y
12 CHS ÷ 13 ÷ CF_j

Then we can use this short program to calculate sin(x):

Cheers
Thomas

(10-28-2014 04:45 AM)Thomas Klemm Wrote: [ -> ]Then we can use this short program to calculate sin(x):

Code:

1/x
1
x<>y
Δ%
STO i
NPV

Thomas - There must be something missing in your code... It sure doesn't work for me, either by entering the angle in degrees or radians.

Jeff K

This is another way to enter the coefficients:

0 CF₀
1 CF_j
0 CF_j
3 n! 1/x CHS CF_j
0 CF_j
5 n! 1/x CF_j
0 CF_j
7 n! 1/x CHS CF_j
0 CF_j
9 n! 1/x CF_j
0 CF_j
11 n! 1/x CHS CF_j
0 CF_j
13 n! 1/x CF_j

You can use RCL CF_j to check your entries. The index n will go down from 13 to 0. Just make sure to set n to 13 again!

This is the program as numeric codes:

These are some examples:

0.1 R/S
0.09983341665

0.2 R/S
0.1986693308

1 R/S
0.8414709848

3.141592654 ENTER 6 ÷
0.5235987757
R/S
0.5000000000

HTH
Thomas

PS: All angles are in radians.
Edit: Added a Nonpareil state file.

With this program the function sin^-1 can be calculated. Just use the same entries for the coefficients as before for sin.


Examples:

0.1 R/S
0.1001674212

0.2 R/S
0.2013579208

0.5 R/S
0.5235987756
6 ×
3.141592654

0.5 √x
0.7071067812
R/S
0.7853981632
4 ×
3.141592653

Cheers
Thomas