Why Does the Divergence of r-hat Over r-squared Equal Zero?

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SUMMARY

The divergence of the unit vector \(\hat{r}\) over the squared modulus \(|r|^2\) equals zero due to the mathematical properties of vector calculus. The unit vector \(\hat{r}\) is defined as \(\hat{r} = \hat{x} + \hat{y} + \hat{z}\), while \(|r|^2\) is expressed as \(x^2 + y^2 + z^2\). The discussion highlights the necessity of proper differentiation techniques to arrive at the correct solution, emphasizing that errors often stem from miscalculating derivatives in vector functions.

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  • Understanding of vector calculus, specifically divergence and differentiation.
  • Familiarity with unit vectors and their properties.
  • Knowledge of the mathematical representation of vectors in three-dimensional space.
  • Proficiency in applying the divergence operator to vector fields.
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  • Review the principles of vector calculus, focusing on divergence and its applications.
  • Study the differentiation of vector functions to avoid common pitfalls.
  • Explore the relationship between unit vectors and their corresponding modulus in three-dimensional space.
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Students and professionals in mathematics, physics, and engineering who are working with vector calculus and need to understand the implications of divergence in three-dimensional vector fields.

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Homework Statement



How divergence of r (cap)/ |r|^2 is equal to zero?



Homework Equations



r(cap)= x(cap)+y(cap)+z(cap)

|r|^2 as x^2+y^2+z^2


The Attempt at a Solution



I tried the problem and end up with with a different solution I took r(cap)= x(cap)+y(cap)+z(cap)
|r|^2 as x^2+y^2+z^2. Tell me where i went wrong?

where r(cap) is unit vector of r vector
|r|^2 is the square of modulus of r
 
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Could you please provide the calculation that lead you to the wrong answer? It is hard to pinpoint where you went wrong otherwise.
 
You didn't differentiate correctly. Show your work.
 
Here's my attempt to the problem
 

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Well ##\mathbf{\hat r} = \mathbf{\hat x} + \mathbf{\hat y} + \mathbf{\hat z}## seems false. You have ##\mathbf{r} = (x,y,z)##. Work from there.
 
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