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ClaudioPedrazzi12-Amethyst
12-Amethyst
February 10, 2022
Solved

Simplifying symbolically an equation keeping pi (Mathcad 15)

  • February 10, 2022
  • 2 replies
  • 2112 views

Hi everyone,

I have an equation that I would like to let Mathcad simplify for me.  It looks like this:

1.PNG

ok 🙂 I know I could simplify it myself, but please consider this an example!

 

If I select the left side and then Symbolics > Simplify I obtain the highly unsatisfying result:

2.PNG

what I would like is that pi remains expressed as pi!

 

I have tried, remembering another thread, the "symbolic undefine" pi:=pi (above the equation) but apparently it does not work!

 

Am I asking Mathcad 15 too much?  

 

thanks for any suggestion!

 

Best regards, Claudio

 

PS: no, I do not use Prime 😉

PS2: the equation is derived with some manipulation from ASME Boiler and Pressure Vessel Code, Section III, and is related to the allowable stress in a pipe product, under known inner pressure and external moments, at design condition.

 

 

Best answer by AlanStevens

Try replacing the 1.5 by 3/2

 

2 replies

V
24-Ruby III
VladimirN24-Ruby III
24-Ruby III
February 10, 2022

 Hi Claudio,

 

Please upload your Mathcad worksheet.

A
AlanStevens19-TanzaniteAnswer
19-Tanzanite
February 10, 2022

Try replacing the 1.5 by 3/2

 

    C
    ClaudioPedrazzi12-AmethystAuthor
    12-Amethyst
    February 10, 2022

    Hey, thanks @AlanStevens it works!  I do not understand why, but it works 🙂

    I also had the thought with fractions and also tried "Format > Result > Fraction" but it gave ugly fractional approximations of the numbers shown above!

     

    W
    Werner_E25-Diamond I
    25-Diamond I
    February 10, 2022

    It works because the symbolic engine has a nasty "feature". Whenever it encounters a decimal point it switches to some kind of float/approximation mode (similar to what you achieve if you add "float,20".

    Werner_E_0-1644501143771.png

     

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