Recent content by dincerekin

  1. D

    Potential difference in a sphere relative to infinity

    there should be a negative sign before this integral and the charge is negative. two negatives make a positive \text{$\Delta $V}=\int _{\infty }^a\frac{1}{4\pi \epsilon }\frac{Q}{r^{2}}dr
  2. D

    Potential difference in a sphere relative to infinity

    well, i thought my answer was too simple/easy to be right i guess.
  3. D

    Potential difference in a sphere relative to infinity

    Homework Statement A thin plastic spherical shell of radius a is rubbed all over with wool and gains a charge of -Q. What is the potential relative to infinity at location B, a distance a/3 from the centre of the sphere?Homework Equations \text{$\Delta $V}=\int...
  4. D

    Proof: limit=0 for any positive integer n

    oh! how didn't I see this before thanks so much <3
  5. D

    Proof: limit=0 for any positive integer n

    it should be \lim_{x\to0}\frac{x^{1-k}}{e^\frac{1}{x^2}}=\lim_{x\to0}\frac{x^{-1}x^{2-k}}{e^\frac{1}{x^2}}
  6. D

    Proof: limit=0 for any positive integer n

    oh sorry, that should be the other way around
  7. D

    Proof: limit=0 for any positive integer n

    so, \lim_{x\to0}\frac{x^{2-k}}{e^\frac{1}{x^2}}=\lim_{x\to0}\frac{x^{-1}x^{1-k}}{e^\frac{1}{x^2}} but i can't simply say that \lim_{x\to0}\frac{x^{-1}x^{1-k}}{e^\frac{1}{x^2}}= \lim_{x\to0}{x^{-1}} × \lim_{x\to0}\frac{x^{1-k}}{e^\frac{1}{x^2}} because \lim_{x\to0}{x^{-1}} doesn't...
  8. D

    Proof: limit=0 for any positive integer n

    so I am trying to show its true for n=k+1 assuming n=k i.e i need to show that \lim_{x\to0}\frac{x^{1-k}}{e^\frac{1}{x^2}}=0 assuming that \lim_{x\to0}\frac{x^{2-k}}{e^\frac{1}{x^2}}=0 im not sure how to manipulate this now?
  9. D

    Proof: limit=0 for any positive integer n

    I applied l'hospital's and simplified a bit and now I've got \frac{n}{2}\lim_{x\to0}\frac{x^2}{e^\frac{1}{x^2}x^n}=0 now what?
  10. D

    Proof: limit=0 for any positive integer n

    Homework Statement Prove that \lim_{x\to0}\frac{e^\frac{-1}{x^2}}{x^n}=0 for any positive integer n. Homework Equations The Attempt at a Solution I've tried using a combination of induction and l'hopital's rule to no avail. Perhaps I am over complicating it? All help is...