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  1. seanieg89

    integration help (MX2)

    you lost a factor of cos(x) spiral.
  2. seanieg89

    complex number

    Yeah its not a polynomial equation in z...
  3. seanieg89

    Interesting Math Problem....

    I wouldn't risk using it in the HSC. The fact that exponentials dominate polynomials which dominate logarithms is given to you without proof. (In one of the Cambridge 3U books I think.)
  4. seanieg89

    complex number

    The correct answer is: z=0,\textrm{cis}\left(\frac{k\pi}{3}\right)\quad{k=0,1,2,3,4,5}
  5. seanieg89

    complex numbers

    The point (2,3) also satisfies the given conditions. So the correct solution is the circle of radius 1 about (-2,-3) and the point (2,3).
  6. seanieg89

    Absolute Value Inequalities

    $Case I: $x\geq -2$.\\ $x+2=|x+2|>3x+7\Rightarrow -2\leq x < -5/2$ which has no solutions.\\ \\ Case II: $x<-2$.\\$-(x+2)=|x+2|>3x+7\Rightarrow x<-9/4\; \; \&\;\; x<-2\Rightarrow x<-9/4$.\\ So our overall solution is $x<-9/4.$ $
  7. seanieg89

    Absolute Value Inequalities

    x < -9/4.
  8. seanieg89

    Music while studying? Distraction or Motivation...?!? What do you think....

    I used to study to metal through a sick pair of headphones. Find it too distracting these days though.
  9. seanieg89

    HSC 2012 MX2 Marathon (archive)

    Re: 2012 HSC MX2 Marathon Don't know what you are expecting us to assume, as arbitrary real powers are not defined in the HSC. But we can make sense of the question using the integral definition of the logarithm, and the log laws/differentiation laws that follow. $Let $x_n:=(1+x/n)^n$. \\...
  10. seanieg89

    Maths in focus

    I strongly recommend Cambridge as it is written by an actual mathematician (Dr Pender). The exposition is clear and the questions are excellent.
  11. seanieg89

    A difficult geometry question.

    Yep, a clever proof by contradiction would be the nicest way of doing it. Alternatively, an ugly coordinate geometry approach will work. Hint: Standard techniques involving congruence/similarity are surprisingly useless here...try playing with inequalities instead.
  12. seanieg89

    A difficult geometry question.

    Prove that any triangle with two internal angle bisectors equal in length is isosceles.
  13. seanieg89

    Area

    (To prove the upper bound in d, bound the integrand above separately on the intervals [0,1/sqrt(2)] and [1/sqrt(2),1].)
  14. seanieg89

    Area

    Options a, b and d are all correct. And none is "more correct" than any other. Perhaps the question asked you to single out the incorrect statement?
  15. seanieg89

    How do you write your sigmas?

    Mine are like carrots but the horizontal segments are rarely equal in length or parallel unless I am making an effort to write something up to show other people / submit for something. When I am figuring stuff out for myself the working jumps all over the page and isn't particularly neat.
  16. seanieg89

    0.9 recurring=1

    Agree with you obviously, but don't really see how the rearrangement of conditionally convergent series relates to this...
  17. seanieg89

    0.9 recurring=1

    Hilberts 'paradox' doesn't really demonstrate the nonexistence of infinity as a real object, it simply provides an example of a counterintuitive mathematical property that infinite sets (as a formal mathematical object) can have: namely that an infinite set can have proper subsets of the same...
  18. seanieg89

    0.9 recurring=1

    Why?. (Not that I disagree with you. I have stated my philosophical view.)
  19. seanieg89

    0.9 recurring=1

    This is just a formal peculiarity of the way we write down numbers: The decimal representation of a real number is not necessarily unique. For similar reasons, 0.1111...=1 in binary. And regarding the existence of infinity 'in reality' one may pose the question: "do real numbers exist?"...
  20. seanieg89

    I just solved this. Can you? (MX2 students should have a go)

    If the Gamma function is used in the question, surely its definition as an integral can be assumed? From there its one substitution and a couple of lines...
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