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Problems(4)

Cyclic Expression Equals Two

Source: Indian RMO 2013 Paper 1 Problem 4

2/1/2014
Find the number of 1010-tuples (a1,a2,,a9,a10)(a_1,a_2,\dots,a_9,a_{10}) of integers such that a11|a_1|\leq 1 and a12+a22+a32++a102a1a2a2a3a3a4a9a10a10a1=2.a_1^2+a_2^2+a_3^2+\cdots+a_{10}^2-a_1a_2-a_2a_3-a_3a_4-\cdots-a_9a_{10}-a_{10}a_1=2.
modular arithmeticcombinatorics unsolvedcombinatorics
Indian RMO- Paper -3

Source: RMO - problem 4

12/11/2013
A polynomial is called Fermat polynomial if it can be written as the sum of squares of two polynomials with integer coefficients. Suppose that f(x)f(x) is a Fermat polynomial such that f(0)=1000f(0)=1000. Prove that f(x)+2xf(x)+2x is not a fermat polynomial
algebrapolynomialquadraticsmodular arithmeticnumber theory unsolvednumber theory
Indian RMO - Paper -4[4]

Source:

12/12/2013
Let xx be a non-zero real numbers such that x4+1x4x^4+\frac{1}{x^4} and x5+1x5x^5+\frac{1}{x^5} are both rational numbers. Prove that x+1xx+\frac{1}{x} is a rational number.
Auxiliary Lines in a Triangle

Source: Indian RMO 2013 Mumbai Region Problem 4

2/1/2014
In a triangle ABCABC, points DD and EE are on segments BCBC and ACAC such that BD=3DCBD=3DC and AE=4ECAE=4EC. Point PP is on line EDED such that DD is the midpoint of segment EPEP. Lines APAP and BCBC intersect at point SS. Find the ratio BS/SDBS/SD.
ratiogeometry unsolvedgeometry