HP Forum Archive 17

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hp17bii+ formula problem, HP response Message #1 Posted by Don Shepherd on 2 Mar 2007, 6:53 p.m. I recently bought a 17bii+ and had problems entering a formula that the solver would accept. I wrote HP, and this is their reply. I'm not sure I understand exactly what they are saying, but they seem to reflect the discussion on this forum recently about this problem. Their recommended solution DOES work, but I heard it first from Bruce, another member of this forum. Their reply: Hello Mr. Shepherd Thank you for your support of HP Calculators. My name is Rainer Boelzle and I am the HP Calculator WW TCE & Support Manager. Thank you for your letter dated 2/24/2007. I forwarded your email to our technical expert and he provided the following feedback: ------------------------------- The user is entering the following formula: 0*L(A: LOG(N)+1)+ sigma(I :1:A:1: MOD(N:10)+ 0*L(N:IP(N/10))) Which is semantically correct, but meaningless. The reason for this is that: The variable A is a 'place holder', not a real variable as it's value is changed all the time (by the L(A: LOG(N)+1). The variable N, the input is also changed all the time by the L(N:IP(N/10)) The solver will try to make the whole equation equal to 0, ie: Sum, LOG(N)+1 times of ( N mod 10, with a division of N by 10 each time). Ie, this equation calculates the sum of the digits in the integer part of N. However, as the solver is iterative (ie it will execute the equation multiple times), after the first calculation, N will be equal to 0 and the solver will stop with whatever value in A and 0 in N... If the user really wants to calculate the sum of the digits of a number he should do like this: DIGITS=0*L(M:N)+sigma(I:1:LOG(N)+1:1:MOD(G(M):10)+0*L(M:IP(G(M)/10))) And he will be able to enter a number in N and solve for digits and get the sum of the digits of the number. Note that he will not be able to do the reverse, ie: enter a value for digits and find a number as this is not a continuous function and the solver can not solve for that... ------------------------------- I hope this helps. Please let me know if I can be of any further assistance. Thank you. Rainer Hewlett-Packard Company 16399 West Bernardo Drive, MS 8-600 San Diego, CA 92127 858-655-6737

Re: hp17bii+ formula problem, HP response Message #2 Posted by Bill (Smithville, NJ) on 2 Mar 2007, 8:16 p.m., in response to message #1 by Don Shepherd Hi Don, Very interesting. I just entered S = 0*L(A: LOG(N)+1)+ sigma(I :1:A:1: MOD(N:10)+ 0*L(N:IP(N/10))) into my HP-19BII and it works great. I'm not sure I understand why the variable A would be changed since the SIMGA is the only area that should be calculated multiple times. It would appear that the re-arranging of the equation is done differently between the 19BII and the 17BII+. I've just started playing around with the solver on the 19BII, so I may not really know what I'm talking about :) Bill

Re: hp17bii+ formula problem, HP response Message #3 Posted by Gene on 2 Mar 2007, 10:18 p.m., in response to message #2 by Bill (Smithville, NJ) Yes, the solver doesn't work the same on the 17b2+ as it did on the 19bII (and original 17bII). That's the reason some things have to be done differently. I AM glad their solution worked. The 19BII solver also had the ability to use the financial functions INSIDE the solver. VERY nice. Unfortunately, they aren't in the 17b2+. Rats!

Re: hp17bii+ formula problem, HP response Message #4 Posted by Peter A. Gebhardt on 3 Mar 2007, 6:37 a.m., in response to message #1 by Don Shepherd Besides the known differences of the HP17bii solver - Isn't it good news, that HP apparently is having at least one person able & willing to support questions in a NON "marketing way" like : "It is not mentioned in the manual - so why do you dumb a** user use it?" I welcome Rainer Boelzle and others from HP coming back to the community in a highly appreciated, supportive way! Thanks a lot HP Calculator Division. Best regards Peter A. Gebhardt Edited: 3 Mar 2007, 6:38 a.m.

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