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## Help please - plotting curve as a series of functions

SOLVED Newbie

## Help please - plotting curve as a series of functions

Hi,

Attached is a mathcad worksheet - when you scroll down you will see a set of questions to my problem and a plot of the function that I have produced to try and plot the curve that I want. The curve I wish to plot should look something like the sketch attached (see curve_sketch file) Plot points on the sketch refer to the nomenclature in the mathcad file.

Many thanks

Omar

1 ACCEPTED SOLUTION

Accepted Solutions Visitor
(in response to uclphd)

## Re: Help please - plotting curve as a series of functions

If you normalise the x parameter for each stage here mod(x)-Xeb then the start point needs a constant added, equal to the result from the previous stage at Xeb in this case already calculated as Rub.

If you calculate everything as mod(x) here, saving the result as a local variable (r).

Then the final answer can be returned as Regards

Andy

10 REPLIES 10 Ruby III
(in response to uclphd)

## Re: Help please - plotting curve as a series of functions

I'll take a look when I have some more time.

In the meantime maybe the following link will be of help concerning plotting of piecewise defined functions.

http://communities.ptc.com/message/170411#170411 Newbie
(in response to Werner_E)

## Re: Help please - plotting curve as a series of functions

Thanks Werner Sapphire III
(in response to uclphd)

## Re: Help please - plotting curve as a series of functions

See if this helps. Newbie
(in response to Fred_Kohlhepp)

## Re: Help please - plotting curve as a series of functions

Hi Fred, thanks for your approach it solves plotting the curve correctly. If you read my response below to Andy I upload a further file - there is a scaler issue in my differential equation that I need to fix to solve my problem.

Many thanks

Omar Visitor
(in response to uclphd)

## Re: Help please - plotting curve as a series of functions

If you normalise the x parameter for each stage here mod(x)-Xeb then the start point needs a constant added, equal to the result from the previous stage at Xeb in this case already calculated as Rub.

If you calculate everything as mod(x) here, saving the result as a local variable (r).

Then the final answer can be returned as Regards

Andy Newbie
(in response to uclphd)

## Re: Help please - plotting curve as a series of functions

Hi Andy,

That's great you've solved the problem for plotting the curve. However I encounter another problem when I apply the curve to my differential equation which I solve using the Runge Kutta method. I have attached an updated version of the mathcad file - if you can please take a look and let me know how I resolve the scaler issue so it solves the differential equation.

Many thanks

Omar Visitor
(in response to uclphd)

## Re: Help please - plotting curve as a series of functions

Hi Omar,

2 problems:

1 You have Rmu * (...

It should be just Rmu(...

& 2 Rmu is set for parameter in m and returning value as N

All the other functions only return number results (no units)

If you remove the units from Rmu (as above) you get an answer.

However, I have tried adding units to the other equations & still get errors!!

So possible that the answer given may not be correct.

Regards

Andy Newbie
(in response to AndyWesterman)

## Re: Help please - plotting curve as a series of functions

Hi Andy

Thanks

Omar Visitor
(in response to uclphd)

## Re: Help please - plotting curve as a series of functions

Hi Omar,

Don't think that I diod anything else to the sheet, so here it is.

If you spot a difference, please let me know

Regards

Andy Newbie
(in response to AndyWesterman)

## Re: Help please - plotting curve as a series of functions

Hi Andy

That works and gives me the sollution i'm looking for. Thank you for your help with this.

Kind regards

Omar