Is there any way to make this equation work on the HP 50g? - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: General Forum (/forum-4.html) +--- 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?