Wikipedia:Reference desk/Archives/Mathematics/April 2009

= April 1 = Reference_desk/Archives/Mathematics/2009 April 1


 * 1) Nonlinear ODEs with linear symmetries
 * 2) Subgraph isomorphism in both directions implies isomorphism?
 * 3) White noise

= April 2 = Reference_desk/Archives/Mathematics/2009 April 2


 * 1) sorting quadratic irrationals with Maple 9
 * 2) Plotting implicit functions
 * 3) calendar question
 * 4) Composed ceilings
 * 5) Game theory terminology

= April 3 = Reference_desk/Archives/Mathematics/2009 April 3


 * 1) Integral comparison text for a rather ugly function
 * 2) mathematics-groups and rings
 * 3) Really easy question
 * 4) Fundamental Theorem of Algebra

= April 4 = Reference_desk/Archives/Mathematics/2009 April 4


 * 1) Rolling hemispheres and moments of inertia
 * 2) Kronecker Delta
 * 3) Aleph numbers and the axiom of choice
 * 4) Dyad
 * 5) Repeated integration
 * 6) Relations on a set X
 * 7) What are the general equations to determine the xy locations of the points of a triangle when given the lengths of the 3 sides and the xy coordinates of one side?
 * 8) Complex power series

= April 5 = Reference_desk/Archives/Mathematics/2009 April 5


 * 1) A question
 * 2) DNE
 * 3) Largest Ordinal
 * 4) Cubic Residues
 * 5) Integral with one of its bounds appearing in the integrand

= April 6 = Reference_desk/Archives/Mathematics/2009 April 6


 * 1) What is this called by definition
 * 2) Maximal subgroups of a group
 * 3) Divergence and Infinity
 * 4) Just a quick answer check - volume integral
 * 5) Testing hypotheses about ratings
 * 6) Converting quadratic Bézier curve into cubic Bézier curve

= April 7 = Reference_desk/Archives/Mathematics/2009 April 7


 * 1) "Measuring a rectangular box"

= April 8 = Reference_desk/Archives/Mathematics/2009 April 8


 * 1) Combination?
 * 2) Solving Congruences
 * 3) unique left/right inverses for functions
 * 4) Ratio and product distributions

= April 9 = Reference_desk/Archives/Mathematics/2009 April 9


 * 1) Apollonian Circles
 * 2) Inequality and greatest integer function
 * 3) Number of combinations with constraints
 * 4) Rule of Three expressed as a Mathematical Formula

= April 10 = Reference_desk/Archives/Mathematics/2009 April 10


 * 1) xy=yx
 * 2) Nontrivial Normal Abelian Subgroups of a Solvable Group

= April 11 = Reference_desk/Archives/Mathematics/2009 April 11


 * 1) Limit involving moment generating functions
 * 2) Graph
 * 3) What symbol is this?
 * 4) how does variable-length testing work?
 * 5) why does modulus of a random integer in a high range favor lower answers SO SLIGHTLY?
 * 6) okay then what is the answer
 * 7) how to do monte carlo properly

= April 12 = Reference_desk/Archives/Mathematics/2009 April 12


 * 1) When (or how do i find out when) the integral of x^P exp(-x^Q) converges over (0, infinity)?
 * 2) Intrinsic equation
 * 3) Invariant sets
 * 4) Factorial proof
 * 5) Conjugate Diameter?
 * 6) Mandelbrot Set

= April 13 = Reference_desk/Archives/Mathematics/2009 April 13


 * 1) Length of a Continued Fraction
 * 2) constructing a table
 * 3) Gaussian Derivative
 * 4) Polynomial question/thing
 * 5) statistics: are there real effects that are impossible to show statistically with very high confidence?
 * 6) Finding P
 * 7) Connection between frequency modulation and Bessel functions

= April 14 = Reference_desk/Archives/Mathematics/2009 April 14


 * 1) Puzzle
 * 2) What is $int sqrt{1-frac{dt^2}{dr^2}} dr$?
 * 3) Repeated Root

= April 15 = Reference_desk/Archives/Mathematics/2009 April 15


 * 1) Composition of functions and integrability
 * 2) Isolated singularities
 * 3) Algebra: Olympiad question

= April 16 = Reference_desk/Archives/Mathematics/2009 April 16


 * 1) Prime number
 * 2) water disturbance equation

= April 17 = Reference_desk/Archives/Mathematics/2009 April 17


 * 1) Is there an infinite number of different types of probability distribution?
 * 2) Functional form of the von-Neumann Morgenstern utility function - any help much appreciated!!!
 * 3) Class number 1

= April 18 = Reference_desk/Archives/Mathematics/2009 April 18


 * 1) Conditional probability in LaTeX
 * 2) Uniform population sampling noise
 * 3) (n-1)-size linearly independent subsets of n vectors
 * 4) Is a given set of group elements a set of coset representatives?
 * 5) Critical graph

= April 19 = Reference_desk/Archives/Mathematics/2009 April 19


 * 1) Splitting lemma

= April 20 = Reference_desk/Archives/Mathematics/2009 April 20


 * 1) Topological properties
 * 2) Simplifying logarithms with Maxima
 * 3) 1. Nf3 f5 2. d4 e6 3. Bg5 Be7 4. Bxe7 Qxe7
 * 4) Numbered system of equations in LaTeX

= April 21 = Reference_desk/Archives/Mathematics/2009 April 21


 * 1) A*B*C = B cubed – B, where A, B and C are successive integers?
 * 2) Quantum mechanics?

= April 22 = Reference_desk/Archives/Mathematics/2009 April 22


 * 1) The Floor Function
 * 2) Factoring a cubic
 * 3) apparent error in pages on kernel smoothing

= April 23 = Reference_desk/Archives/Mathematics/2009 April 23


 * 1) In geometry, is a square with rounded corners still considered a square? If not, what is it called, mathematically?
 * 2) Quotient spaces, and cell complexes

= April 24 = Reference_desk/Archives/Mathematics/2009 April 24


 * 1) Growth of a bacterial colony
 * 2) sci.mathresearch newsreader question
 * 3) Polynomial division
 * 4) Holomorphic mapping
 * 5) How to compute statistical significance of correlation

= April 25 = Reference_desk/Archives/Mathematics/2009 April 25


 * 1) higher derivatives
 * 2) dice
 * 3) Poker theory and cardless poker
 * 4) A large slice of pie
 * 5) Upper bound on the number of topologies of a finite set
 * 6) Homework problem

= April 26 = Reference_desk/Archives/Mathematics/2009 April 26


 * 1) Convert a computer file to a non-negative Integer number
 * 2) Birthday paradox
 * 3) The Gateaux derivative - how is it defined?
 * 4) Pólya enumeration theorem
 * 5) Example in the article about the Hermite interpolation
 * 6) Digit distribution

= April 27 = Reference_desk/Archives/Mathematics/2009 April 27


 * 1) The Greatest Integer Function
 * 2) Why is "dense-in-itself" a useful notion?
 * 3) Proving or disproving a homeomorphism with [0,1]
 * 4) Can every unit algebraic number be expressed as a root of unity?
 * 5) Disjoint balls into a ball in R^n

= April 28 = Reference_desk/Archives/Mathematics/2009 April 28


 * 1) Łukasiewicz notation for propositional functions
 * 2) Easy probability question
 * 3) The set of complex numbers is the largest possible set of numbers?

= April 29 = Reference_desk/Archives/Mathematics/2009 April 29


 * 1) Evaluating very small natural logs
 * 2) Integral - confusion

= April 30 = Reference_desk/Archives/Mathematics/2009 April 30


 * 1) house payment