A195489 - OEIS

%I #5 Mar 30 2012 18:57:47

%S 1,8,1,7,3,6,3,6,0,0,5,7,5,5,1,7,6,2,3,7,6,2,6,3,8,9,1,1,6,4,7,5,9,5,

%T 6,6,8,5,4,1,3,7,5,2,6,2,5,3,1,7,7,8,7,3,9,7,1,8,3,3,8,4,8,0,5,1,0,8,

%U 2,7,7,5,8,9,2,3,7,3,9,2,9,8,2,4,3,6,3,5,9,0,1,2,3,5,2,5,2,6,7,3

%N Decimal expansion of shortest length, (C), of segment from side CA through centroid to side CB in right triangle ABC with sidelengths (a,b,c)=(sqrt(7),3,4).

%C See A195304 for definitions and a general discussion.

%e (C)=1.817363600575517623762638911647...

%t a = Sqrt[7]; b = 3; h = 2 a/3; k = b/3;

%t f[t_] := (t - a)^2 + ((t - a)^2) ((a*k - b*t)/(a*h - a*t))^2

%t s = NSolve[D[f[t], t] == 0, t, 150]

%t f1 = (f[t])^(1/2) /. Part[s, 4]

%t RealDigits[%, 10, 100] (* (A) A195487 *)

%t f[t_] := (t - a)^2 + ((t - a)^2) (k/(h - t))^2

%t s = NSolve[D[f[t], t] == 0, t, 150]

%t f2 = (f[t])^(1/2) /. Part[s, 4]

%t RealDigits[%, 10, 100] (* (B) A195488 *)

%t f[t_] := (b*t/a)^2 + ((b*t/a)^2) ((a*h - a*t)/(b*t - a*k))^2

%t s = NSolve[D[f[t], t] == 0, t, 150]

%t f3 = (f[t])^(1/2) /. Part[s, 1]

%t RealDigits[%, 10, 100] (* (C) A195489  *)

%t c = Sqrt[a^2 + b^2]; (f1 + f2 + f3)/(a + b + c)

%t RealDigits[%, 10, 100] (* Philo(ABC,G) A195490 *)

%Y Cf. A195304.

%K nonn,cons

%O 1,2

%A _Clark Kimberling_, Sep 19 2011