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  1. Affinity

    Using the software R

    can you give a more detailed example?
  2. Affinity

    An Interesting question that yet lies unanswered

    it's finite.. all of them have to be positive integers
  3. Affinity

    An Interesting question that yet lies unanswered

    what about uniqueness/knowing that all solutions are found
  4. Affinity

    Determing growth rate of a sequence

    write k for floor(n^2/10) then we know that a_n = k(k+1)/2 we also know that n^2/10 - 1 < k <= n^2/10 so (n^2/10)(n^2/10 - 1)/2 < a_n <= (n^2/10)(n^2/10 + 1)/2 both bounds ~ n^4/200 and so does a_n
  5. Affinity

    Harder Parabola Question

    you're looking at something along the lines of (everything above the line) http://www.wolframalpha.com/input/?i=plot+%283%2F4^%281%2F3%29%29+*+%28x^2%29^%281%2F3%29+%2B+2 for a = 1. Don't think this is suitable for 4U.. essentially you need to figure out which parameters would make a cubic...
  6. Affinity

    complex locus - help

    arg z[z-(root3 +i)] = pie/6 write a = sqrt(3) + i let p+iq = w = z - a/2 = (x - sqrt(3)/2 ) + (y-1/2)i arg( (z - a/2)^2 - a^2 /4 ) = pi/6 arg( w^2 - a^2 /4 ) = pi/6 arg( (p^2 - q^2 - 1/2) + i(2pq - sqrt(3)/2 ) = pi / 6 (2pq - sqrt(3)/2 ) / (p^2 - q^2 - 1/2) = 1/sqrt(3)...
  7. Affinity

    Integrating Complex Numbers

    If you are talking about complex valued functions (f:R --> C) then it's relatively straight forward because you can consider f(x) = g(x) + i*h(x) where g, h are regular real functions. What gets interesting is when you consider complex functions ie f:C --> C. for one \int_a^b f(z) dz where...
  8. Affinity

    complex locus - help

    the original question: http://www.wolframalpha.com/input/?i=plot+sqrt%283%29%28x^2+-+y^2+-+1%29+%3D+2xy remove the parts in the 2nd and 4th qudarant
  9. Affinity

    Patel Conics question.

    (2)'s wrong.. in (1) you assumed that (x1,y1) is on the circle, so you can't use it as a point on the hyperbola. you should solve (1) and x^2 - 2y^2 = 4 simultaneously and set the discriminant to 0. Actually.. the better way: Here's what I tried: Equation of tangent to circle: x[x1] + y[y1] =...
  10. Affinity

    need this 4 past paper urgent!

    I don't have the paper, but you might want to specify the year too.
  11. Affinity

    complex numbers

    slightly more elementary: (1 - \omega_1) \times \left(\sum_{i=1}^{n} \omega _i\right) =\sum_{i=1}^{n} \omega _i - \sum_{i=1}^{n} \omega _i = 0 and since (1-\omega_1) is not 0, you know that the sum is 0
  12. Affinity

    inequalities with x in the denominator

    you don't really need to multiply through by the denominator.. (2x-3)/(x-2)>1 (2x-4 + 1)/(x-2)>1 2 + [1/(x-2)]>1 1/(x-2) > -1 ==> x-2 > 0 or x-2 < -1 x > 2 or x < 1
  13. Affinity

    how to prove duality thm (fourier transform qn)

    not that simple, you need some analysis to go about these things
  14. Affinity

    Harder inequalities

    depends on the order your techers taught you guys
  15. Affinity

    Steps in recursive induction?

    The first and third lines gives the definitions of U_n, your job is to show taht the middle one is equivalent to the def.,
  16. Affinity

    4unit is just too complex

    your method is also ok. but "Then using z^n + 1/z^n = 2cosnθ" is wrong, it only works for z on the unit circle. (z^3 + 1/z^3) + 15(z + 1/z) = 0 (z + 1/z)^3 + 12(z + 1/z) = 0 (z + 1/z)((z + 1/z)^2 + 12) = 0 (z + 1/z)((z + 1/z) - 2isqrt(3))((z + 1/z) + 2isqrt(3)) = 0 (z^2 + 1)(z^2 - 2isqrt(3)z...
  17. Affinity

    4unit is just too complex

    you can just substitute and verfy for this q. if you want to solve it.. there are other ways: alternate method: (z+1)^6 = (-1)*(z-1)^6 taking 6ths roots we get, z+1 = w*(z-1) where w is a 6th root of -1 so z = (1+w)/(1-w) let w' be the conjugate of w and w = cos(a) + isin(a) z =...
  18. Affinity

    Induction in 4unit

    Not really.. There's an algebraic proof.
  19. Affinity

    integration

    One reminder .. the integral of 1/x is (ln |x|) not (ln(x))
  20. Affinity

    Complex No.

    almost there :) arg(a-b) -arg(c-b) is the angle at b
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