Finding the Q1 Values for A, B & C: A Puzzling Homework Task!

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The discussion revolves around determining the values of Q1 for AB, AC, and CB, specifically why they are 5, -5, and -2, respectively. The original poster questions the method used to derive these values from the known quantities at points A, B, and C. It is clarified that the values provided are trial solutions, which are initial guesses that can be adjusted through iteration to achieve the correct results. Participants emphasize that any set of values that maintains the overall balance can serve as an initial guess. The conversation concludes with inquiries about the rules for selecting these initial guesses and their potential impact on the final outcomes.
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Homework Statement


why the Q1 for AB is 5 ? for Ac is -5 , while for CB is -2 ? how to determine them ?
I could only see Qat A = 10.0 , Q at C = 3 , Q at B = 7
P/ s: the author take clockiwse direction to be positive , anticlockwise direction to be negative ...

Homework Equations

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is the author wrong ?
 
foo9008 said:
is the author wrong ?
can someone show Q1 for AB is 5 ? for Ac is -5 , while for CB is -2 ?
 
anybody can try to answer this ? i have been waiting for the explanation too long .
 
foo9008 said:
anybody can try to answer this ? i have been waiting for the explanation too long .
It's a problem when you reply to your own post that other readers think you've had a reply unless they follow the link to the thread.
foo9008 said:
why the Q1 for AB is 5 ? for Ac is -5 , while for CB is -2 ? how to determine them ?
It's only a trial solution. Any values could have been used that add up correctly.
 
haruspex said:
It's a problem when you reply to your own post that other readers think you've had a reply unless they follow the link to the thread.

It's only a trial solution. Any values could have been used that add up correctly.
what do you mean by trial solution ? I'm confused... how did the author get the Q= 5, -5 , and -2 based on 10 , 3 and 7 ?
 
foo9008 said:
what do you mean by trial solution ? I'm confused... how did the author get the Q= 5, -5 , and -2 based on 10 , 3 and 7 ?
I mean it is just an initial guess, consistent with the 10, 3 and 7. The method goes through an iteration to get closer to the actual solution. As an exercise, you could start with 6, -4 and -1 instead and check that you end up with the same final answer.
 
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haruspex said:
I mean it is just an initial guess, consistent with the 10, 3 and 7. The method goes through an iteration to get closer to the actual solution. As an exercise, you could start with 6, -4 and -1 instead and check that you end up with the same final answer.
is there any rule to choose the 3 numbers for initial guess? e.g , if i choose the first number is 15 , will it affect the second and third number that i am choosing ? or it is just guessing ?
 
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