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  • Complex Analysis Entire Functions Question?

    True of False: If f is an entire function satisfying f(0) = 1 and f'(n) = f(n) for all integers n>=1, then f(z) = e^z for all z in C.

    1 réponseMathematicsil y a 9 ans
  • Cauchy-Riemann Equations Question?

    If a complex-valued function fails to satisfy the Cauchy-Riemann equations, does this imply that it is not differentiable anywhere or that it merely fails to be analytic (meaning there might still exist points at which it is differentiable)?

    2 réponsesMathematicsil y a 10 ans
  • Complex Analysis Line Integral Question?

    I'm having trouble evaluating the line integral around the curve y(t) = e^it, 0 <= t <= 2pi (unit circle) of Re(f) where f(z) = z. I substituted y(t) in for f which gave me

    Re(y(t)) = Re(e^it) = Re(cos(t) + isin(t)) = cos(t)

    and y'(t) = ie^it

    so our integral is equivalent to the integral from 0 to 2pi of their product, namely cos(t)ie^it. Is this the correct procedure? Because at this point I tried to evaluate this integral by parts and got 0 but the answer should be i(pi).

    1 réponseMathematicsil y a 1 décennie
  • Infinite Arctan Series?

    Given a sequence a_1 = 2, a_2 = 8, ... , a_n = 4a_(n-1) - a_(n-2), n >= 3, show that

    π/12 = sum (n=1 to ∞) arctan((a_n)^2).

    2 réponsesMathematicsil y a 1 décennie
  • Combinatorial Identity Question?

    Prove sum (from k = 0 to n-1) C(n, k)C(n+2-k, 3) = (n/3)(n + 2)(n + 7)2^(n-4)

    2 réponsesMathematicsil y a 1 décennie
  • Number Theory: Prove n divides 2^n - 2 if...?

    Let p be a prime number with p > 3 and let n = (2^(2p) - 1)/3. Prove n|(2^n - 2).

    1 réponseMathematicsil y a 1 décennie
  • Prove that there is no integer n>1 for which n|(2^n - 1)?

    Prove that there is no integer n>1 for which n|(2^n - 1).

    4 réponsesMathematicsil y a 1 décennie
  • Power of 3 with a string of 2008 consecutive zeros?

    Does there exist a power of 3 (number of the form 3^n) with a string of 2008 consecutive zeros in its decimal expansion?

    4 réponsesMathematicsil y a 1 décennie
  • Triangle of Friends?

    There are three schools each with n students. Every student is friends with at least n+1 students from the other schools. Prove that there is some trio of students (one from each school) that are mutual friends.

    1 réponseMathematicsil y a 1 décennie
  • There are 2n people at a hotel. Each person knows exactly n other people. Prove they can be paired up...?

    There are 2n people at a hotel where n is a postive integer. Each person knows exactly n other people. Prove that they can be paired up and assigned to rooms so that everyone knows his/her roommate.

    Note: The knowing relation is mutual so A knows B implies B knows A

    2 réponsesMathematicsil y a 1 décennie
  • Boxes and Coins Game?

    There is a game involving 5 boxes numbered 1, 2, 3, 4, and 5 containing 0, 20, 30, 40, and 50 coins respectively. The game has two players (A and B) who take turns alternately. It begins with A taking some coins from some box n and moving them to box n-1. (For example A could take 23 coins from box 4 and move them to box 3 so that the boxes have 0, 20, 53, 17, 50 coins respectively. Then B might take 2 coins from box 2 and move them to box 1 so that the boxes have 2, 18, 53, 17, 50 coins respectively.) You cannot move any coins that are in box 1. When all the coins have been moved to box 1 the game is over. The player who makes the last move wins. Which player has a winning strategy and what is it?

    1 réponseMathematicsil y a 1 décennie
  • Number Theory?

    If n is a natural number such that 2n+1 and 3n+1 are perfect squares, prove that 5n+3 can't be a prime number.

    1 réponseMathematicsil y a 1 décennie
  • Simultaneous System of Equations?

    Let a and b be positive real numbers with a >= b. Let p be the maximum value of a/b for which the system of equations

    a² + y² = b² + x² = (a - x)² + (b - y)²

    has a solution in (x, y) satisfying 0 <= x < a and 0 <= y < b. Find p.

    1 réponseMathematicsil y a 1 décennie
  • Sequence containing perfect square?

    Let f(n) = n + [sqrt(n)]. Prove that for every positive integer m, the sequence

    m, f(m), f(f(m)), f(f(f(m))), ...

    contains the square of an integer.

    Note: [x] represents the greatest integer less than or equal to x.

    2 réponsesMathematicsil y a 1 décennie
  • Greatest Integer Function Proof?

    Let n be a natural number. Prove that

    [(n+1) / 2] + [(n+2) / 4] + [(n+4) / 8] + [(n+8) / 16] + ... = n.

    For a cleaner version of the problem see the link below:

    http://www.artofproblemsolving.com/Classroom/cbe6/...

    5 réponsesMathematicsil y a 1 décennie
  • Triangles in a circle?

    Two nonoverlapping arcs of a circle are chosen. Eight distinct points are then chosen on each arc. All 64 segments connecting a chosen point on one arc to a chosen point on the other arc are drawn. How many triangles are formed that have at least one of the 16 chosen points as a vertex?

    2 réponsesMathematicsil y a 1 décennie
  • 10-digit numbers divisible by 11111?

    How many 10-digit numbers have all distinct digits and are multiples of 11111?

    2 réponsesMathematicsil y a 1 décennie
  • Challenge: Trig Sum?

    Find the least positive integer n such that

    [1 / (sin(45)sin(46))] + [1 / (sin(47)sin(48))] + ... + [1 / (sin(133)sin(134))] = 1 / sin(n).

    4 réponsesMathematicsil y a 1 décennie
  • Triangle Inequality?

    Let a, b, and c be the sides of a triangle and S its area. Prove

    a^2 + b^2 + c^2 >= (4S)sqrt(3).

    Where does equality hold?

    4 réponsesMathematicsil y a 1 décennie
  • Complicated Fraction?

    Compute

    [(10^4 + 324)(22^4 + 324)(34^4 + 324)(46^4 + 324)(58^4 + 324)] / [(4^4 + 324)(16^4 + 324)(28^4 + 324)(40^4 + 324)(52^4 + 324)].

    7 réponsesMathematicsil y a 1 décennie