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inverse transform returns 'variable undefined

ptc-1716002
1-Visitor

inverse transform returns 'variable undefined

Attempting to perform an inverse Laplace transform
on a simple 2nd order polynomial (2 poles, 1 zero)

The symbolic operation works, but when I attempt to
assign the result to a function, Mathcad 12.1 always
returns "This variable is undefined".

Suggestions anyone?
5 REPLIES 5
RichardJ
19-Tanzanite
(To:ptc-1716002)

It appears to be a bug in version 12. It works fine in versions 11, 13 and 14. I can't actually check it in version 12 though because it's such a lemon version of Mathcad last time I changed PC I couldn't be bothered to install it along with all the others. Perhaps someone else that has version 12 installed can check.

Richard

On 2/16/2010 3:57:16 PM, rijackson wrote:
>It appears to be a bug in version 12.

Without version 12 I guess that the bug is in the t variable: try to add ",t" in the inverse laplace. Also, write t:=t after t:=0.

If not, must to manual assign the impulse function by copy & paste.

Regards. Alvaro.

I recommend that you upgrade to Mathcad 14, which you can do for only $99 including all extension packs and libraries at http://www.ptc.com/go/mathcad99.

Mona
StuartBruff
23-Emerald III
(To:mzeftel)

On 2/17/2010 10:33:47 AM, MonaZ wrote:
== I recommend that you upgrade to Mathcad 14, which you can do for only $99 including all extension packs and libraries at http://www.ptc.com/go/mathcad99.

And, as someone with no commercial interest in Mathcad, I think that's pretty good advice. M14 is significantly better than M12.

Stuart

Mathcad 12 doesn't seem to like vectors in its inverse laplace transform! Replace by scalars and it works ok - see attached.

stv
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