This led him to discover the ‘method of separation of variables’
1691 A year later he formulated the ‘method of solving the homogeneous
differential equations of the first order’ He went further in a very short time
to the discovery of the ‘method of solving a linear differential equation of the
first-order’ How surprising is it that all these methods came from a single man
and that too within 25 years of the birth of differential equations