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+--- Thread: Is there any way to make this equation work on the HP 50g? (/thread-10516.html)
Is there any way to make this equation work on the HP 50g? - nathanpc - 04-15-2018 09:11 PM
I'm writing a simple program in my 50g to be able to get the frequency response of a electronic low-pass filter. The equations are pretty simple to understand, so I decided to try and write a simple program and this is what I have come up with:
Code:
%%HP: T(0)A(D)F(.);
\<<
100 @ Resistor value.
0.000001 @ Capacitor value.
-3 @ Cutoff point (dB).
0 @ Temporary value for "fn".
\-> r c fs fn
\<<
'-(1/(2*‡*f*c))*i' EVAL 'c' STO @ Get capacitor complex impedance.
'fs=20*LOG(ABS(c)/ABS(r+c))' EVAL 'fn' STO @ Frequency response function.
fn 'f' ISOL @ Isolate f.
DUP @ Create a backup.
EVAL @ Should return the value of "f".
\>>
\>>The problem is that when I run it I get the following message "ISOL Error: Not reducible to a rational expression". I know this is because of the limitations of the solver in the HP 50g, but is there any way to make this work?
RE: Is there any way to make this equation work on the HP 50g? - nathanpc - 04-15-2018 10:00 PM
I just tried something similar in my HP Prime and I was successful by running the same equation through the fsolve function like this:
Code:
fsolve(fs,f,0..30000)And I was able to get the answer, 1587.77482493 in this case. Is there a equivalent solver function in the HP 50g where I can put a range of guesses?