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Help! "This variable is undefined"

dpons
1-Newbie

Help! "This variable is undefined"

I'm trying to use Mathcad to solve a series of equations. I keep getting the error message WhatsApp Image 2017-04-08 at 4.49.36 PM.jpeg"This variable is undefined" Any tips?

1 ACCEPTED SOLUTION

Accepted Solutions
Werner_E
24-Ruby V
(To:dpons)

1) You forgot to type multiplication dots when calculating A.t * (....). If you write A.t(...) then A.t is interpreted as function.

2) You have a unit mismatch in your second equation. The first summand has to be multiplied by a length (I had simply multiplied by 1m which sure is not correct)

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4 REPLIES 4
Werner_E
24-Ruby V
(To:dpons)

1) You forgot to type multiplication dots when calculating A.t * (....). If you write A.t(...) then A.t is interpreted as function.

2) You have a unit mismatch in your second equation. The first summand has to be multiplied by a length (I had simply multiplied by 1m which sure is not correct)

dpons
1-Newbie
(To:Werner_E)

Thank you! Very helpful.

It intrigued me that your first solve block worked but the second one didn't.  I found two things from Werner's unit balance:

  • , and
  • You need to define A_t and A_s the same: 

These, along with Werner's fixes . . .

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