Invariant analysis of nonlinear fractional ordinary differential equations with Riemann-Liouville fractional derivative

A systematic method is given to derive Lie point symmetries of nonlinear fractional ordinary differential equations and illustrate its applicability through the fractional Riccati equation and nonlinear fractional ordinary differential equation of Lienard type with Riemann-Liouville fractional derivative. Using the obtained Lie point symmetries, we construct their exact solutions wherever possible.