Recent content by U.Renko

  1. U

    PhD MUST be on same area as masters degree?

    I see thank you very much for your answers. I was kind of gettting worried about it.
  2. U

    PhD MUST be on same area as masters degree?

    I'm still an undergraduate but I was wondering about the future and all that. I do like love physics as a whole, but I don't think there is a subfield which I REALLY like or REALLY dislike. I also like "versatility" as a way of life. So I was wondering: "can I move to and from subfields as I...
  3. U

    Complex Countour Integral. not sure how to solve.

    You're right. I was a bit in doubt about this to tell you the truth. But either way, the point is, I can't use Cauchy's theorem. Ah, yes, I've heard about. Although I haven't studied it yet so... Guess I'll be revisiting this problem later
  4. U

    Complex Countour Integral. not sure how to solve.

    Homework Statement So, as far as I understand, there is not much difference between integrals in complex variables and those pesky line integrals from vector calculus. I'm not particullary good with line integrals, so it follows that I'm not quite understanding the complex variables ones...
  5. U

    Vector calculus identities proof using suffix notation

    Nope. it doesn't make sense. what was I thinking...
  6. U

    Vector calculus identities proof using suffix notation

    I must become good at this ASAP. Homework Statement prove \vec{\nabla}\cdot (\vec{a}\times\vec{b} ) = \vec{b} \cdot(\vec\nabla\times\vec{a}) - \vec{a}\cdot(\vec\nabla\times\vec{b}) Homework Equations \vec a \times \vec b = \epsilon_{ijk}\vec a_j \vec b_k \vec\nabla\cdot =...
  7. U

    Complex numbers polynomial divisibility proof

    Well... now that you mention it I'm not quite sure I have an argument for that...
  8. U

    Complex numbers polynomial divisibility proof

    I'm not sure whether this should go in this forum or another. feel free to move it if needed Homework Statement Suppose that z_0 \in \mathbb{C}. A polynomial P(z) is said to be dvisible by z-z_0 if there is another polynomial Q(z) such that P(z)=(z-z_0)Q(z). Show that for...
  9. U

    Help understanding proof involving Maxwell equation

    help understanding "proof" involving Maxwell equation I'm currently taking a course on mathematical methods for physics. (Like always I'm a bit confused about where exactly I should post these questions, should it go to the homework forum? ) anyway as I was reading the lecture notes I...
  10. U

    Finding current and charge in a RC circuit.

    yes, that is what I meant. I honestly don't know where I messed up with the LaTeX though...
  11. U

    Finding current and charge in a RC circuit.

    hmm let's see: \int_{0}^{t} \frac{\epsilon}{R}e^{\frac{t}{RC}}dt = qe^{\frac{t}{RC} solving the left hand side by substitution gives: C\epsilon\left(e^{\frac{t}{RC} -1 \right) = qe^{\frac{t}{RC} and so: q(t)= e^{\frac{-t}{RC}C\epsilon\left(e^{\frac{t}{RC} -1 \right) q(t)=...
  12. U

    Finding current and charge in a RC circuit.

    Homework Statement A resistor with resistance R and a capacitor with capacitance C are connected in series to a direct current battery ε. find the current and charge on the circuit as function of time. it looks more like a review of differential equations, so I'm not really sure if I...
  13. U

    Basic Group Theory Proof. Looks easy, might not be.

    Homework Statement Let a,b be elements of a group G. Show that the equation ax=b has unique solution. Homework Equations none really The Attempt at a Solution ax = b . Multiply both sides by a^{-1}. (left multiplication). a is guaranteed to have an inverse since it is an element of a...
  14. U

    How Do Adults Navigate Life with Social Dysfunction?

    Have you heard about exposure therapy? For example, for people with arachnophobia they first show videos of spiders, then progress to watching spiders in a glass from far away. Then closer, then even closer. Eventually they may even catch the spider on hand as if never had the phobia in the...
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