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HP Forum Archive 04

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HP 15C
Message #1 Posted by Lisa on 8 Oct 2000, 7:35 p.m.

I need help using the matrix function of my hp 15c. Any instruction would be much appreciated.

Re: HP 15C
Message #2 Posted by William L. Drylie on 9 Oct 2000, 10:07 p.m.,
in response to message #1 by Lisa

Lisa. The section in the manual for Calculating With Matrices is about 41 pages. If you e-mail your address to me, I would send you a reprint. For now, I will get you started with an example from the manual. The 15c can work with up to 5 matrices which are named A through E using the 15's corresponding A through E keys. You can specify the size of each matrix, store and recall values of matrix elements and perform matrix operations with complex and real elements. Consider the example.

3.8x1 + 7.2x2 = 16.5 1.3x1 - 0.9x2 = -22.1 determine the values of x1 and x2. Keystrokes: g CF 8 deactivates complex mode. 2 Enter f DIM A dimensions matrix A to be 2X2 f Matrix 1 prepares for automatic entry of matrix elements in user mode. f USER turns on user annunciator 3.8 STO A Denotes Matrix A row 1 column 1 7.2 STO A 1.3 STO A .9 CHS STO A 2 ENTER 1 f DIM B Dimensions matrix B to be 2X1 16.5 STO B 22.1 CHS STO B f RESULT C designates matrix C storing the result. RCL MATRIX B RCL MATRIX A / press divide key RCL C displays 1, 1 (row 1, column 1) -11.2887 (value of (X1)) RCL C 8.2496 (value of (X2)) f USER deactivates user mode f MATRIX 0 Clears all matrices.

The solution to the system is X1 = -11.2887 ans X2 = 8.2496. Up to 64 matrix elements can be stored in memory. Use all 64 in one matrix or distribute them among up to 5 matrices. Matrix inversion can be performed on an 8X8 with real elements or a 4X4 with complex elements. If you have need of further help, I suggest you e-mail me directly at I will help more. Or e-mail mailing address, I will send you 15C reprint of matrix section of manual. Good luck. I still have fun using my 15C at work. I can also provide many an engineering example from my daily work and programs. Let me know. Bill.

Re: HP 15C
Message #3 Posted by Tom Liang on 16 Oct 2000, 5:12 p.m.,
in response to message #1 by Lisa

I have an out-of-production HP15C, but I have misplaced the basic user's manual, although I have the advanced manual. There is an annoying "c" indicator on the lower level of the window and slightly more than three-quaters to the right. I have a guess as to think that it indicates "complex" mode. But when I when I hit the "Re><Im" button, nothing happens to the "c." Can someone help me? Thanks.

Re: HP 15C
Message #4 Posted by Bill Smith (oregon) on 16 Oct 2000, 7:12 p.m.,
in response to message #3 by Tom Liang

you're right, it is in complex mode.

to deactivate complex mode, clear flag 8 (g CF 8).

Re: HP 15C
Message #5 Posted by on 17 Oct 2000, 9:23 a.m.,
in response to message #4 by Bill Smith (oregon)

Yes, SF 8 activates complex mode and CG 8 desactivates it.

Another amazing sutff with the flags is SF 9 activates flashing display and CF 9 desactivates it...

Re: HP 15C
Message #6 Posted by tom drewski on 17 Oct 2000, 1:04 p.m.,
in response to message #5 by

Hi Thibaut. Still busy?

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