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  1. gurmies

    Quick Complex Numbers Q

    From \,\, where \,\, you \,\, left \,\, off: \\\\ \tan\frac{\theta}{2}\left ( \frac{\sin\frac{\theta}{2}+i\cos\frac{\theta}{2}}{\cos\frac{\theta}{2}+i\sin\frac{\theta}{2}} \right ) = itan\frac{\theta}{2}\left (...
  2. gurmies

    First Place in Course

    Congratulations to Michael and Wendy, well deserved - no doubt.
  3. gurmies

    Complex Numbers/Polynomials

    Probably, but for n > 2 - you'd assume arctan(b/a) was workable.
  4. gurmies

    Complex Locus

    Thank you cyl123, clever.
  5. gurmies

    Complex Locus

    I'm trying to think why, algebraically, the condition is true. There is definitely an explanation.
  6. gurmies

    Complex Locus

    Also as an aside, if you tan both sides of the equation, you find yourself dealing with tan[pi/2], which is of course, undefined.
  7. gurmies

    Complex Locus

    Technically x < 0 is still a true statement. For the other branch of the circle, where x > 0, the governing equation would be arg(z-i)-arg(z+i)=-pi/2 or, with some rearranging, arg(z+i)-arg(z-i)=pi/2.
  8. gurmies

    Complex Locus

    The necessary condition should be x < 0.
  9. gurmies

    pH equation

    H2SO4 + 2KOH ---> K2SO4 + 2H2O n(H2SO4) = 0.120 x 0.2 = 0.024 n(KOH) = 0.065 x 0.08 = 0.0052 Now, with 0.0052 moles KOH, there should be 0.0052/2 = 0.0026 moles H2SO4 (note mole ratio). However, we have 0.024 moles H2SO4. Therfore, the amount of H2SO4 in excess is 0.024-0.0026 =...
  10. gurmies

    Complex numbers De Moivres thereom

    (\cos\theta+i\sin\theta)^{4}=\cos4\theta+i\sin4\theta \,\, [By \,\, De \,\, Moivre's \,\, Theorem] \\\\ By \,\, the \,\, Binomial \,\, Theorem, \,\, (\cos\theta+i\sin\theta)^{4}=\cos^{4}\theta+4i\sin\theta\cos^{3}\theta-6\sin^{2}\theta\cos^{2}\theta-4i\sin^{3}\theta\cos\theta+\sin^{4}\theta \\\\...
  11. gurmies

    Who here has got a tutor????

    You don't need tutoring for those subjects ( necessarily ). Give it a go first and don't doubt yourself.
  12. gurmies

    Conics Question - Ellipse.

    Maybe for MX2 this attitude will get you far enough...
  13. gurmies

    implicit differentiation

    LOL, I had typed something similar to this, but then thought meh. Glad someone said it xD
  14. gurmies

    Conics Question - Ellipse.

    Ellipse/Proofs - Wikipedia, the free encyclopedia This should help.
  15. gurmies

    Conics Question - Ellipse.

    This is because when you derive the formula of an ellipse, you end up with x^2/a^2 + y^2/a^2(1-e^2) = 1. We let b^2 = a^2(1-e^2) to make things neater and simpler, I think.
  16. gurmies

    locus question

    w=\frac{z-i}{z-2} \\\\ Let \,\, z=x+iy \\\\ w = \frac{x+i(y-1)}{x-2+iy} \\\\ = \frac{x+i(y-1)}{x-2+iy}\times \frac{x-2-iy}{x-2-iy} \\\\ = \frac{x(x-2)-ixy+i(x-2)(y-1)+y(y-1)}{(x-2)^{2}+y^{2}} \\\\ Re(w)=Re(\frac{x(x-2)-ixy+i(x-2)(y-1)+y(y-1)}{(x-2)^{2}+y^{2}})=0 \\\\ \therefore x(x-2)+y(y-1)=0...
  17. gurmies

    Complex Numbers Question

    z^{3}=8=8cis0 \\\\ z = 2cis\left ( \frac{2k\pi}{3} \right ), \,\, k=0,\pm 1 \\\\ z = 2, \,\, 2cis\frac{2\pi}{3}, \,\, 2cis(-\frac{2\pi}{3}) \\\\ = 2, \,\, -1+i\sqrt{3}, \,\, -1-i\sqrt{3}
  18. gurmies

    Russkaya?

    Russkaya?
  19. gurmies

    Help !

    Where the hell did I get (a,0) from?...this is what happens when you abstain from maths for even one week.
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