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Offline LordMike  
#1 Posted : 01 May 2010 20:17:48(UTC)
LordMike


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How do I compare two formulas?

Like, if I simplify by hand, or solve for x by hand - and I'd like to check if I did it correctly.
What I want to compare, are two equations...

For example:
y = ax + b

And then compare to:
x = (y - b ) / a

And have it reply with "True".

As compared to if I wrote x = (- y - b ) / - a
Offline omorr  
#2 Posted : 03 May 2010 05:32:23(UTC)
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Helo Mike,

At the moment, for this kind of problem you have to use some CAS (Maxima maybe?)
Code:

 Solve over x
>:: sol1:=solve(y=a*x+b,x)
 
                                        y - b
                                   [x = -----]
                                          a
 
 Solved by hand
>:: sol2:=(-y-b)/a
 
                                     - y - b
                                     -------
                                        a
 
 Compared
>:: if(at(x,sol1)=sol2) then "true" else "false"
 
                                      false
 
 Compared
>:: if(at(x,sol1)=(y-b)/a) then "true" else "false"
 
                                      true

Regards,
Radovan

Edited by user 03 May 2010 13:04:02(UTC)  | Reason: Not specified

When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
Offline LordMike  
#3 Posted : 05 May 2010 04:35:18(UTC)
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Ah, so it is not possible :P

Thanks for reply Wink
Offline Andrey Ivashov  
#4 Posted : 09 May 2010 02:05:03(UTC)
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LordMike wrote:
Ah, so it is not possible :P

Why? Acute


(download source file)

Best regards.
Offline omorr  
#5 Posted : 09 May 2010 03:12:22(UTC)
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Hello,

I was thinking in this direction, but unfortunately this is not so simple. Please see the examples.
Wrong answer "true", it should be "false":

Neither "true" nor "false". If statement needs the numerical result of the logical contidion.


Regards,
Radovan



When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
Offline Andrey Ivashov  
#6 Posted : 09 May 2010 03:35:01(UTC)
Andrey Ivashov


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Ok, then we can use this stuff:


(download source file)

Regards.
Offline omorr  
#7 Posted : 09 May 2010 03:58:28(UTC)
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Hello Andrey,

Yes, I think you are right Good . We were thinking on the same thing at this very moment.

Regards,
Radovan
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
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