Equation in solve app not solving
04-30-2015, 01:26 AM
Post: #1
 Alfon Junior Member Posts: 12 Joined: Apr 2014
Equation in solve app not solving
Hi,
I put an equation into the Solve app- E1-

L= (P)* (1- (1/(1+R)^N))/R

Then put numerical values into L,P,R and tried to solve for N. I did this by pressing the Num key on the calculator then first pressing Blue-Shift clear to zero out anything in the variables then entering values. Then highlighted the value I wanted to solve for and pressed Solve then nothing happened.
It remained 0 (incorrectly).

Am I missing something here?
04-30-2015, 03:55 AM
Post: #2
 Tim Wessman Senior Member Posts: 2,097 Joined: Dec 2013
RE: Equation in solve app not solving
Which variable? What values did you enter?

TW

Although I work for the HP calculator group, the views and opinions I post here are my own.
05-01-2015, 07:19 PM
Post: #3
 John Colvin Member Posts: 170 Joined: Dec 2013
RE: Equation in solve app not solving
The formula will solve for N with the appropriate guess values for the other variables. By clearing out all of the variables to zero, you will always get a "Bad Guess" error.
For example: L = 100, P = 50, R = 0.25 and solving for N gives N = 3.10628...
05-13-2015, 11:37 PM
Post: #4
 Alfon Junior Member Posts: 12 Joined: Apr 2014
RE: Equation in solve app not solving
Unfortunately it seems the solver app doesn't work right. I used eg L=100000 P=2000 R= 0.00281, tried to solve for N and nothing happened. Then I used my HP 50 and got the correct result (N=53.95...). I tried several other values as well, but the result doesn't come up correctly on the Prime?
05-14-2015, 12:00 AM
Post: #5
 Helge Gabert Senior Member Posts: 460 Joined: Dec 2013
RE: Equation in solve app not solving
Works fine for me in the solve app (53.956...). Version 6975.

What are your home settings? Did you try fsolve?
05-14-2015, 12:02 AM
Post: #6
 Marcio Senior Member Posts: 438 Joined: Feb 2015
RE: Equation in solve app not solving
The same here. In actually, this is one of the few areas where the Prime outperforms the 50g.
05-14-2015, 12:23 AM (This post was last modified: 05-14-2015 12:52 AM by Alfon.)
Post: #7
 Alfon Junior Member Posts: 12 Joined: Apr 2014
RE: Equation in solve app not solving
Changed integers setting in Home Settings to Binary (was some other value before) and it works! Thanks.

PS subsequently also checked the digit grouping Setting in Home--looks like the , (comma) used for thousand place holder was giving me this error.
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