Hier brauchst du die p-q-Formel
x^2 - 2x - (n+pi) = 0
p = -2
q = -(n+pi)
x12 = -p/2 +- sqrt((p/2)^2-q)
x1 = 1 + sqrt(1+(n+pi))
x2 = 1 - sqrt(1+(n+pi))