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problem with the solving function

sweapon
1-Visitor

problem with the solving function

hello

i have been having this problem when solving an equation, i think im doing everything ok, but when i use the solve function i returns like a numeric equation with units, anyones know how to workaround this one?

ACCEPTED SOLUTION

Accepted Solutions
Werner_E
25-Diamond I
(To:sweapon)

Mathcad's symbolics doesn't know anything about units and treats them as unknown variables. m and mm are two different variables as seem by the symbolics and so they are not cancelled/simplified.

Solution is to assign the symbolic calculation to a variable and let this variable evaluate numerically.

1.png

Or you can also use an inline evalution if you just want to check the variabe kn and do not intend to use it later.

2.png

If you only want a numeric solution, you could also do without any symbolics and use a solve block

3.png

or the root() function

3b.png

If, on the other hand, you used the symbolic solve on purpose and you had expected a general symbolic result, you would have to clear all variables in use for symbolics evaluation. Your posting is missing the information what kind of result you have expected, you simply wrote that you didn't like what you got:

4.png

or follow it with a numeric inline evaluation

4b.png

View solution in original post

6 REPLIES 6
Werner_E
25-Diamond I
(To:sweapon)

Mathcad's symbolics doesn't know anything about units and treats them as unknown variables. m and mm are two different variables as seem by the symbolics and so they are not cancelled/simplified.

Solution is to assign the symbolic calculation to a variable and let this variable evaluate numerically.

1.png

Or you can also use an inline evalution if you just want to check the variabe kn and do not intend to use it later.

2.png

If you only want a numeric solution, you could also do without any symbolics and use a solve block

3.png

or the root() function

3b.png

If, on the other hand, you used the symbolic solve on purpose and you had expected a general symbolic result, you would have to clear all variables in use for symbolics evaluation. Your posting is missing the information what kind of result you have expected, you simply wrote that you didn't like what you got:

4.png

or follow it with a numeric inline evaluation

4b.png

hi

Thank your worksheet looks really good, but for some reason i cannot create them in my own spreadsheet, it still appears like symbolic

Untitled.png

Werner_E
25-Diamond I
(To:sweapon)

Sorry, I can't debug a picture.

Obviously there is an error message you don't show.

What did you change compared to the file you sent and I sent back?

You will have to send the sheet for further examination.

It seems you are looking for a numeric solution, so I guess using a numeric appraoch like the solve block I showed is the better choice anyway.

See if these help. (Version 11 may not work.)

Thanks Fred and Werner, im still having the problem of the normal solving function,but thanks to you i have found workarounds

Thanks

Werner_E
25-Diamond I
(To:sweapon)

I don't experience the error you showed in your last postwhen I open your worksheet (with Mathcad 15 M030).

Which version of Mathcad are you using?

This is what I see when i open your sheet (the very last line was added by me to show the value of kn).

05.05.png

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