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

[foo9008]

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

The Attempt at a Solution

 

[foo9008]

is the author wrong ?

 

[foo9008]

is the author wrong ?

can someone show Q1 for AB is 5 ? for Ac is -5 , while for CB is -2 ?

 

[foo9008]

anybody can try to answer this ? i have been waiting for the explanation too long .

 

[haruspex]

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.

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.

 

[foo9008]

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 ?

 

[haruspex]

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.

 

[foo9008]

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 ?