Calculating Vectors: A, B, and C

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The discussion revolves around calculating vector operations for vectors A, B, and C defined as A(2,1,1), B(1,-1,0), and C(-1,1,-1). Users seek assistance with various vector calculations, including the magnitudes of A and B, the sum of vectors A and B, scalar multiplication of vector C, and the dot and cross products. Clarifications are provided on the difference between the magnitude of individual vectors and the magnitude of their sum. Additionally, the angle between the vectors is linked to understanding the dot product. Overall, the thread emphasizes the importance of grasping vector addition, scalar multiplication, and product operations for solving the homework problems.
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Homework Statement


I cannot find other sources to help me with this problem set, I have A B and C vectors defined by: A (2,1,1) B(1,-1,0), C(-1,1,-1)
From these I have a list of questions and some I am stuck on are:each of these are vectors with an arrow above it
1. |A| + |B| this I did as √ax^2 +ay^2 +az^2 + √the same for B
2. |A + B| but how do i do this, what is the difference between these?

3. A + B

4. 3C

5. A dot (B X C)

8. What is the angle between A and B, A and C, and B and C? in radians use pi

id appreciate any help!
 
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organgeatom said:
1. |A| + |B| this I did as √ax^2 +ay^2 +az^2 + √the same for B

This would be correct.

organgeatom said:
2. |A + B| but how do i do this, what is the difference between these?

This is asking for you the magnitude of (vector A + vector B), question 1 was asking you for the magnitude of vector A + the magnitude of vector B. Start by first calculating what A+B is, how do you add two vectors together?


organgeatom said:
3. A + B

The same as question 2.


organgeatom said:
4. 3C

Do you know how to multiply a vector by a scalar?

organgeatom said:
5. A dot (B X C)

Do you know the terms 'dot product' and 'cross-product'?

organgeatom said:
8. What is the angle between A and B, A and C, and B and C? in radians use pi

This question depends on if you can do question 5.
 
Wikipedia explains the basic properties of vectors such as addition, scalar multiplication, length as well as dot and cross products.
 
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Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks
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