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function composed from another functions - "solve" does not work

function composed from another functions - "solve" does not work

function composed from another functions - "solve" does not work

(OP)
Hi,

I have a function composed from another 3 functions and I like to obtain points where f(x) = 0. So in attached I expect 4 values, but solve does not work. Please help.

Regards

RE: function composed from another functions - "solve" does not work

(OP)
GregLocock, did you open the attached ? On my computer when try to "solve" MYY(x) MYY is in red and note sais "This variable is undefined"...or do you see on your computer a result ?

RE: function composed from another functions - "solve" does not work

Quote:

On my computer when try to "solve" MYY(x) MYY is in red and note says "This variable is undefined"...or do you see on your computer a result ?
That's not what it says on mine: "polycoeff" is not defined, ergo MY(x) is not defined, ergo MYY(x) is not defined.

RE: function composed from another functions - "solve" does not work

(OP)
Occupant, maybe better to post a printscreen in this case, I guess that you have set default value for array origin to zero, I have array origin set to one. And hope you can see clearly, that MYY(x) is plotted so it have to be defined

RE: function composed from another functions - "solve" does not work

I would use the minerr function.

Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com

 

RE: function composed from another functions - "solve" does not work

Oops, or the root function.

Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com

 

RE: function composed from another functions - "solve" does not work

The setting of ORIGIN goes with the worksheet, why would I have changed it? "polycoeff" is not a Mathcad function and not defined in the worksheet you submitted, therefore, it creates an error. The obvious conclusion is, you uploaded only a portion of your worksheet. How can you expect to get help with an error that you yourself created by submitting this?

RE: function composed from another functions - "solve" does not work

skjoex,

It maybe that mathCAD's symbolic solve command cannot solve for x when MYY(x) is a function with embedded if/then logic.  Either way, pretty impressive worksheet.

Oh..and polycoeff *is* a MathCAD function in my version (v14).  Maybe Occupant's conclusion isn't so obvious. ;)

Steve

Stephen Seymour, PE
Seymour Engineering & Consulting Group
www.seymourecg.com  

RE: function composed from another functions - "solve" does not work

Quote:

Oh..and polycoeff *is* a MathCAD function in my version (v14).  Maybe Occupant's conclusion isn't so obvious. ;)

I have to admit, I am not using v14 but v13 and I had to go back to find out. If you're right, how come "polycoeff" turned red (in V14-M020 and V13, of course) and I got "this variable is undefined". If it was a function recognized by Mathcad, I should have gotten "this function does not apply here" or some such thing.
 

RE: function composed from another functions - "solve" does not work

It's actually part of the Data Analysis Extension Pack, which should have come with Mathcad 14.:

polycoeff(vx, vy) Takes two real vectors of the same length vx and vy and returns the coefficients of the interpolating polynomial function

TTFN

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