Julia Pitre jdp8657

Week 10 Problem 6.4.4

url: http://people.tamu.edu/~jdp8657/homework.html

Problem: Here A is a vector field and f is a scalar function. One of these identities is correct, one is sheer nonsense, and one is sensible but numerically wrong. Label which is which and correct the one with the numerical error.< /P>

  1. Ñ . ( f A) = (Ñ f) . A + f (Ñ x A )
  2. Ñ . ( f A) = (Ñ f) . A - 2f (Ñ . A )
  3. Ñ . (Ñ x A ) = 0

Solution:

  1. is nonsense
  2. should correctly read Ñ . ( f A) = (Ñ f) . A + f Ñ . A
  3. is true