Wolfram Cloud Document

N =

1

π ≃ 4*\*UnderoverscriptBox[\(∑\), \(n = 1\),[ToBoxes[nfin, StandardForm]]\)\)]\)\*FractionBox[SuperscriptBox[\((\(-1\))\), \(n - 1\)], \(2*n - 1\)]\) = \*DynamicBox[ToBoxes[N[Sum[Times[4, Times[Power[-1, Plus[n, -1]], Power[Plus[Times[2, n], -1], -1]]], List[n, 1, nfin]]], StandardForm]]\)

Error relative to π:

0.858407

	N = 1
π ≃ 4\UnderoverscriptBox[\(∑\), \(n = 1\),[ToBoxes[nfin, StandardForm]]\)\)]\)\FractionBox[SuperscriptBox[\((\(-1\))\), \(n - 1\)], \(2n - 1\)]\) = \*DynamicBox[ToBoxes[N[Sum[Times[4, Times[Power[-1, Plus[n, -1]], Power[Plus[Times[2, n], -1], -1]]], List[n, 1, nfin]]], StandardForm]]\)
Error relative to π: 0.858407