Hypocycloid and Lattice points (noch nicht übersetzt)
A hypocycloid is the curve drawn by a point on a small circle rolling inside a larger circle. The parametric equations of a hypocycloid centered at the origin, and starting at the right most point is given by:
x(t)=(R−r)cos(t)+rcos(R−rrt) y(t)=(R−r)sin(t)−rsin(R−rrt)
Where R is the radius of the large circle and r the radius of the small circle.
Let C(R,r) be the set of distinct points with integer coordinates on the hypocycloid with radius R and r and for which there is a corresponding value of t such that sin(t) and cos(t) are rational numbers.
Let S(R,r)=∑(x,y)∈C(R,r)|x|+|y| be the sum of the absolute values of the x and y coordinates of the points in C(R,r).
Let T(N)=∑NR=3∑⌊R−12⌋r=1S(R,r) be the sum of S(R,r) for R and r positive integers, R≤N and 2r<R.
You are given:
C(3,1) | = | {(3,0),(−1,2),(−1,0),(−1,−2)} |
C(2500,1000) | = | {(2500,0),(772,2376),(772,−2376),(516,1792),(516,−1792),(500,0),(68,504),(68,−504), |
(−1356,1088),(−1356,−1088),(−1500,1000),(−1500,−1000)} |
Note: (−625,0) is not an element of C(2500,1000) because sin(t) is not a rational number for the corresponding values of t.
S(3,1)=(|3|+|0|)+(|−1|+|2|)+(|−1|+|0|)+(|−1|+|−2|)=10
T(3)=10;T(10)=524;T(100)=580442;T(103)=583108600.
Find T(106).