Eliminating arbitrary constants m and c from y=mx+c.
dydx=m. Differentiating again, d2ydx2=0⋯(2) The two arbitrary constants have been eliminated and we have got a differential equation of second order.In the light of above we can say that if an equation contains n arbitrary constants, the result of elimination these constants will be a differential
equation of nth order. Equation (1)in ths above examples are called the General solution of
differential equation. Hence we can say that by solving a differential equation of nth order, we mean to find a relation between the two variables x,y and n independent arbitrary constants, such that when these constants are eliminated the given differential equation of nth order will be formed.