## 185 Reputation

3 years, 221 days

## MaplePrimes Activity

### These are replies submitted by jrive

@Carl Love  -- I appreciate the advice.  Can you give me an example of how you would have done it?

Thanks!

## excellent, thank you....

@acer  --I  was disliking the position dependency of indets.  I'll give what you suggest a shot.

Thank you.

## "parametric" does the trick...

@Carl Love  thanks for your help.  Not sure how it works, but "parametric" did the trick.

Thanks!

Jorge

## re: great stuff, thank you!...

@acer --this is exactly what I wanted to do.  Great.  - and thanks for raising my awareness about potential roundoff erros due to the combinations of large and small values.

Thank you.

## great stuff, thank you!...

@acer thank you again.!  Let me see if I cna follow what you did in the worksheet....

@acer did you mean to attach the  variants you mentioned?

## nice!...

@acer  -- I have a lot of learning to do!

Thank you!

Jorge

@acer following your previous example, I tried the following:

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I was expecting to be able to get the answer down to  1/(sqrt(Ceq) sqrt(L1)) per the substitutions above.  It would be better still if I could get the final answer to display 1/(sqrt(Ceq L1)).

Thanks again!

## Ok - great- Thank you. additional commen...

@acer  -- perfect, thank you!!!

## Ok - great- Thank you. additional commen...

@acer thank you.

There's something I don't get...I have three unknowns (assuming C1=C2), so not sure why I can't use the inequality.  I occurs to me I could instead use C1=C2 in the system of equations (restricting the gain to 1)  - maybe that'll work.

I still need to look at this further, though.   The solution for  R1 results in an imaginary value which shouldn't be the case....

## not really...

@acer what you're seeing are typos when I entered the data on here, since I could not cut and paste it directly from my Maple doc.

Currently, I get this error and have not been able to resolve it, no matter what I try:

sys := {`&omega;res` = 0.1635*10^8*2*Pi, simplify(z3res) = 9 + 0.000150*I, 1 <= abs(vores/vin)}

sol2 := solve(sys, {C1, C2, L1, R1})

Warning, solve may be ignoring assumptions on the input variables.
Error, (in unknown) invalid input: SolveTools:-Inequality expects its 1st argument, eqns, to be of type ({list, set})({`<`, `<=`, `=`}), but received [C2 < 0, And(-(-1+signum(0, C1+C2, 1))*Pi <= Pi, -Pi < -(-1+signum(0, C1+C2, 1))*Pi)]

(I can't figure out how to copy Maple input onto here --the formatting gets all messed up.)  Please see attached file.

Thanks for any pointers!  filter.mw

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Solution

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## how did it solve for you?...

@Kitonum thank you.  What did you change to get it to solve for you?  I never was able to get the solution you got; is it because you entered the formulas into sys, as opposed to the variables to which they were assigned?  (eg. you entered 1<=abs(C1/C2, instead of abs(vores/vin)>=1?

Thanks again

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