I give this complicated primitive function here (Maple 9 used): Analytic solution (Weinberg S. Gravitation and Cosmology, 1972, General Relativity definitions used from this book). Defintion areas: u=1.843608337*10^(-15), 0r=5.424145573*10^(-14) cm, u=1/r,0=P=Pi. u:=P-(-8.905287066*10^(-19)*cos(P)+3.686326146*10^(-15)) / (-cos(P) +1); ta:=P-0.14273426*10^18*arctan(19556.51583*(0.4000000000 *10^15-1506485618*sin(P)^2)^(1/2)*sin(P)/(-0.2000000000*10^15+753242809*sin(P)^2))-0.1021331259*10^48*(0.4000000000*10^15-1506485618*sin(P)^2)^(1/2)*sin(P)/((-0.2000000000*10^15+753242809*sin(P)^2)*(0.37747221 28*10^26+0.1443670077*10^35*(0.4000000000*10^15-1506485618*sin(P)^2)*sin(P)^2/(-0.2000000000*10^15+753242809*sin(P)^2)^2))+0.19991 51856*10^(-30)*((-0.2000000000*10^15+753242809*sin(P)^2)*(-1+sin(P)^2))^(1/2)*(0.3908757305*10^66*(1-sin(P)^2)^(1/2)*(0.4000000000*10^15-1506485618*sin(P)^2)^(1/2)*EllipticF(sin(P),0.1940673606*10^(-2))*sin(P)^2+0.6697771796*10^73*(1-sin(P)^2)^(1/2)*(0.4000000000*10^15-1506485618*sin(P)^2)^(1/2)*EllipticF(sin(P),0.1940673606*10^(-2))+0.2468340123*10^75*sin(P)+0.9296297238*10^69*s in(P)^5-0.2468349419*10^75*sin(P)^3+0.1234170061*10^68*(1-sin(P)^2)^(1/2)*(0.4000000000*10^15-1506485618*sin(P)^2)(1/2)*EllipticE(sin(P),0.1940673606*10^(-2)*sin(P)^2+0.211478707*10^75*(1-sin(P)^2)^(1/2)*(0.4000000000*10^15-1506485618*sin(P)^2)^(1/2)*EllipticE(sin(P),0.1940673606*10^(-2))-0..1273248266*10^68*(1-sin(P)^2)^(1/2)*(0.4000000000*10^15-1506485618*sin(P)^2)^(1/2)*EllipticPi(sin(P),-0.5835906962*10^(-7),0.1940673606*10^(-2))*sin(P)^2-0.2181748740*10^75*(1-sin(P)^2)^(1/2)*(0.4000000000*10^15-1506485618*sin(P)^2)^(1/2)*EllipticPi(sin(P),-0.5835906962*10^(-7),0.1940673606*10^(-2)))/((0.2000000000*10^15+753242809*sin(P)^4-0.2000007532*10^15*sin(P)^2)^(1/2)*(0.2202892715*10^19*sin(P)^2+0.3774722128*10^26 )*cos(P)*(0.4000000000*10^15-1506485618*sin(P)^2)^(1/2));