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J
Jay1-Visitor
1-Visitor
July 1, 2013
Solved

I need help understanding these results. ALl comments & suggestions welcomed. Thanks

  • July 1, 2013
  • 2 replies
  • 2549 views

I'm sure there's something fundamental that I'm overlooking.

Best answer by Werner_E

When in doubt, ask the symbolics for the exact results. The symbolics does not know anything about units and would treat them as variables, so I omitted them.

arcsec2.png

2 replies

W
Werner_E25-Diamond I
25-Diamond I
July 1, 2013

Obviously a conflict between the way the function is defined and the numerical algorithm used. You get very different results whether you chose Romberg or Adaptive method (rightclick menu).

You get the result you expect if you split the integral at 0.1 Hz yourself.

arcsec.png

W
Werner_E25-Diamond IAnswer
25-Diamond I
July 1, 2013

When in doubt, ask the symbolics for the exact results. The symbolics does not know anything about units and would treat them as variables, so I omitted them.

arcsec2.png

J
Jay1-VisitorAuthor
1-Visitor
July 1, 2013

Werner,

Thank-you very much for your time and help. Your suggestions and reminders about the numerical integration process (both sheets) were very helpful and appreciated. Thanks for the tutorial and pointing me in the right direction.

Jay

W
Werner_E25-Diamond I
25-Diamond I
July 1, 2013

You are welcome.

Nevertheless its still unclear to me why Mathcad's numerics fails that bad.

Mathcads symbolics wont operate on a function defined by if (neither programmed nor using the if-function).

So I rewrote it using the Heaviside function.

The numerics still fails

arcsec3.png

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