HI Aspirant,

In differential equations on putting the limit hen a(x) or b(x) [or both] are singular x = x0, in which case the point x = x0 is called a singular point of the differential equation.The point is known as regular singular point since it is maintained at an regular instant.ordinary and singular points are easily extended to the case of homoge- neous nth order linear differential equations.

Hope it helps!