Recent content by Drako Amorim

  1. Drako Amorim

    I Limit of a two variable function

    It's a disk with radius approaching to 0. In case 0 <= t <= 2pi is independent and the limit become: \lim_{r\rightarrow 0}\frac{r^3 \cos^3(t)+r^3 \sin^3(t)}{r\cos(t)+r^2\sin(t)}. If t=pi/2 or 3pi/2 -> cos(t)=0 and sin(t)=+-1 and the limit converge to 0. Else we can do this: \lim_{r\rightarrow...
  2. Drako Amorim

    I Limit of a two variable function

    Yes. x=t and y=0 so the limit will be: \lim_{(t)\rightarrow (0)}\frac{\sin t^{3}}{t}=\lim_{(t)\rightarrow (0)}t^2\frac{\sin t^{3}}{t^3}=0. x=0, y=t: \lim_{(t)\rightarrow (0)}\frac{\sin t^{3}}{t^2}=\lim_{(t)\rightarrow (0)}t\frac{\sin t^{3}}{t^3}=0. x=y=t: \lim_{(t)\rightarrow (0)}\frac{\sin...
  3. Drako Amorim

    I Limit of a two variable function

    ok. L'hospital rule was applied in this limit: \lim_{(0,y)\rightarrow (0,0)}\frac{\sin y^{3}}{y^{2}}. edit: In fact this was a dumb way to solve this simple limit. You have a proof for this? Because paths do not are sufficient. Can you show me in algebra what you see?
  4. Drako Amorim

    I Limit of a two variable function

    The limit is not 0? If you apply the L'hospital method it will give 0. Can you show me what you're saying? You are saying that you can separate \frac{sin(x^3+y^3)}{x+y^2} into f(x)g(y)? About your question: This limit is a challenge that came from \lim_{(x,y)\rightarrow (0,0)}\frac{\sin...
  5. Drako Amorim

    I Limit of a two variable function

    Can you be more clear?
  6. Drako Amorim

    I Limit of a two variable function

    \lim_{(x,y)\rightarrow (0,0)}\frac{\sin (x^{3}+y^{3})}{x^{3}+y^{3}}\frac{x^{3}+y^{3}}{x+y^{2}}=\lim_{(x,y)\rightarrow (0,0)} \frac{x^{3}+y^{3}}{x+y^2}=\lim_{(x,y)\rightarrow (0,0)} \frac{(x+y^{2}-y^{2})x^{2}+(x+y^{2}-x)y}{x+y^2}=\lim_{(x,y)\rightarrow (0,0)}...
  7. Drako Amorim

    I Limit of a two variable function

    Ok. \lim_{(x,y)\rightarrow (0,0)}\frac{\sin (x^{3}+y^{3})}{x^{3}+y^{3}}\frac{x^{3}+y^{3})}{x+y^{2}}=\lim_{(x,y)\rightarrow (0,0)}\frac{x^{3}+y^{3}}{x+y^{2}} The only progress that I have was reduce the limit to this: \lim_{(x,y)\rightarrow (0,0)}\frac{\sin...
  8. Drako Amorim

    I Limit of a two variable function

    I'm trying to verify that: \lim_{(x,y)\rightarrow (0,0)}\frac{\sin (x^{3}+y^{3})}{x+y^{2}}=0. 0<\sqrt{x^2+y^2}<\delta\rightarrow |\frac{\sin (x^{3}+y^{3})}{x+y^{2}}|<\epsilon 0\leq |\sin (x^{3}+y^{3})|\leq |(x^{3}+y^{3})|\leq |x|x^2+|y|y^2 |\frac{\sin (x^{3}+y^{3})}{x+y^{2}}|\leq \frac{...
  9. Drako Amorim

    Unconventional capacitors connection

    Redraw the Delta circuit for a Pi And I conclude that: Vac = (q1 - q3)/Cy Vbc = (q2 + q3)/Cx Vab = q3/Cz = Vac + Vcb = Vac - Vbc → q3/Cz = (q1 - q3)/Cy - (q2 + q3)/Cx → q3 (Cy Cz + Cx Cz + Cx Cy)/(Cx Cy Cz) = q1/Cy - q2/Cx ∴q3 = Cx Cy Cz / (CyCz + CxCz + Cx Cy) [q1/Cy - q2/Cx] ≡ K...
  10. Drako Amorim

    Unconventional capacitors connection

    This problem came from the twelfth edition Sears & Zemansky Electromagnetism, is one of the challenging problems. I think that I solved it and I will transcribe it, but I think that problem is unfair, because there's no 2-port network in the main text
  11. Drako Amorim

    Unconventional capacitors connection

    Homework Statement Hello everyone. The problem is related to these two capacitor connections: In the enunciate it is said that these two are equivalent and it is requested to prove that: C1=(CxCy+CyCz+CzCx)/Cx C2=(CxCy+CyCz+CzCx)/Cy C1=(CxCy+CyCz+CzCx)/Cz Homework Equations C=Q/Vab...
  12. Drako Amorim

    Unconventional capacitors connections

    Sorry, I have posted in the wrong place :'(
  13. Drako Amorim

    Unconventional capacitors connections

    Hi everyone, the problem is related to these two capacitor connections: In the enunciate it is said that these two are equivalent and it is asked to prove that: My problem with these solution is that I do not know how analyze them, because of the two potencial difference. Can you please...
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