Absolute value bars in dot product derivation

In summary, the absolute value bars in this derivation signify the length of the vector rather than the absolute value of a number. This convention was more common in earlier vector math books, but the double v-bar notation is now more widely used.
  • #1
ChiralSuperfields
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Dose someone please know why they have the absolute value bars in this derivation?

1679290283120.png

many thanks!
 
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  • #2
The absolute value bars indicate the length of the vector not absolute value of a number.

Of course, the vector length is always positive.

I think this convention was more popular in early vector math books where as now they use the double v-bar notation.

https://en.wikipedia.org/wiki/Norm_(mathematics)
 
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  • #3
jedishrfu said:
The absolute value bars indicate the length of the vector not absolute value of a number.

Of course, the vector length is always positive.

I think this convention was more popular in early vector math books where as now they use the double v-bar notation.

https://en.wikipedia.org/wiki/Norm_(mathematics)
Thank you for your help @jedishrfu !
 

1. What is the purpose of absolute value bars in dot product derivation?

The absolute value bars in dot product derivation are used to ensure that the resulting value is always positive. This is important because the dot product is a measure of the similarity or correlation between two vectors, and a negative value would indicate a negative correlation.

2. How are absolute value bars used in the dot product formula?

In the dot product formula, the absolute value bars are used to enclose the values of the two vectors being multiplied together. This ensures that the resulting value is always positive, regardless of the signs of the individual components of the vectors.

3. Can the absolute value bars be removed from the dot product formula?

No, the absolute value bars cannot be removed from the dot product formula. Doing so would change the meaning of the formula and could result in incorrect calculations.

4. Why is the dot product sometimes referred to as the absolute value of the projection of one vector onto another?

The dot product can be thought of as the absolute value of the projection of one vector onto another because it measures the length of the projection of one vector onto another, regardless of the angle between the two vectors.

5. Are there any alternative ways to represent the dot product without using absolute value bars?

Yes, there are alternative ways to represent the dot product without using absolute value bars. For example, the dot product can also be calculated using the cosine of the angle between the two vectors multiplied by the magnitudes of the vectors. However, using absolute value bars is the most commonly used and accepted method for calculating the dot product.

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