d 2 x μ d λ 2 + Γ ν ρ μ d x ν d λ d x ρ d λ = 0 {\displaystyle {\frac {{d^{2}}{x^{\mu }}}{d{\lambda ^{2}}}}+\Gamma _{\nu \rho }^{\mu }{\frac {d{x^{\nu }}}{d\lambda }}{\frac {d{x^{\rho }}}{d\lambda }}=0}
