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02-23-2021
04:07 PM

02-23-2021
04:07 PM

Hi all,

I need some help plotting graphs. I have defined the function f(t) however Mathcad still says the function is undefined. Please provide solution. I have attached a screenshot have a look.

Solved! Go to Solution.

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02-23-2021
07:37 PM

02-23-2021
07:37 PM

For more versatility I would make the peak voltage V an argument of all functions involved:

You don't need symbolical evaluation for plotting, but of course you could inspect the values of the coefficients that way:

If the last symbolic representation is important for you, you may try to define A1 and B1 separately like A0 and let the sum beginning from n=2.

Prime 6 sheet attached

9 REPLIES 9

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02-23-2021
04:59 PM

02-23-2021
04:59 PM

Re: Mathcad not able to plot a graph?

In order to plot, Prime needs the function to be numerically known. That means that all symbols you use must be numerically defined, have a value.

In your function you have two DIFFERENT symbols V, one is blue, it is a unit (for Volt), and while that is numerically defined as 1 V, you have defined the function such that you transform it symbolically. The symbolic processor, which is happy to deal with (numerically undefined) symbols, doesn't know about units and treats them as (unknown) symbols. So it transforms the V into a V. Now you want to plot it. That's a task for the numeric processor, that doesn't know the value of V, and (rightfully) complains that the function is 'undefined'.

Possible solutions:

1. Don't transform the function symbolically.

2. Define V:=1 V. before the function definition.

Success!

Luc

So now you ask: But what about *t *, I didn't define *t* numerically?

Prime allows ONE variable to be undefined for a plot, that is the argument to the function, which it automatically and invisibly (behind the scenes) defines as a range variable from -10 to 10. That's why the plot shows that range along the x-axis.

But it's OK to override that automatic definition If you define t:=0,0.1...1 before the plot, it'll plot your function from t=0 to 1 in steps of 0.1.

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02-23-2021
05:46 PM

02-23-2021
05:46 PM

Re: Mathcad not able to plot a graph?

okay so I avoid doing the symbolic transformation and then define t and then it should work? Have a look at this file, is this what you wanted me to do?

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02-23-2021
07:37 PM

02-23-2021
07:37 PM

For more versatility I would make the peak voltage V an argument of all functions involved:

You don't need symbolical evaluation for plotting, but of course you could inspect the values of the coefficients that way:

If the last symbolic representation is important for you, you may try to define A1 and B1 separately like A0 and let the sum beginning from n=2.

Prime 6 sheet attached

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02-24-2021
03:53 AM

02-24-2021
03:53 AM

Re: Mathcad not able to plot a graph?

I want to ask why doesn't it work when v(1,t) and it gives the wrong answer when symbolic arrow is used for B(n) it ends up giving zero? Are these limitations in the software like we discussed previously?

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02-24-2021
06:55 AM

02-24-2021
06:55 AM

Re: Mathcad not able to plot a graph?

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02-24-2021
10:38 AM

02-24-2021
10:38 AM

Re: Mathcad not able to plot a graph?

@AS_9824434 wrote:

I don't know why the symbolics behave like it does. Sometimes we find a workaround for a problem or limitation, sometimes we don't.

But wrong results as given by the new symbolic in Prime 6 and later versions sure are not limitations but severe bugs.

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02-24-2021
12:17 PM

02-24-2021
12:17 PM

Re: Mathcad not able to plot a graph?

Isn't prime 6 the latest version? I've heard prime 7 will be out soon, so will it use the same symbolic engine as prime 6?

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02-24-2021
12:59 PM

02-24-2021
12:59 PM

Re: Mathcad not able to plot a graph?

@AS_9824434 wrote:

As far as I know Prime 7 is scheduled for the beginning of march.

Prime 6 contains two symbolic engines (the legacy MuPad and the new one).

Prime 7 will contain the new engine only. Lets hope that they will improve it.

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02-25-2021
09:15 AM

02-25-2021
09:15 AM

Re: Mathcad not able to plot a graph?

Mathcad Prime 7 will be released on March 2nd, 2021.