YY = Y1^2 t0 = X1^2 aXX = a*t0 Ap = YY+aXX t1 = Z1^2 t2 = 2*t1 t3 = t2-Ap B = 2*t3 xB = aXX*B yB = YY*B t4 = YY-aXX AA = Ap*t4 F = AA-yB G = AA+xB t5 = yB+AA xE = X1*t5 t6 = xB-AA yH = Y1*t6 zF = Z1*F zG = Z1*G X3 = xE*zF Y3 = yH*zG Z3 = zF*zG T3 = xE*yH