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 In the old days, what we now call the ‘solution’ of a differential equation,
was used to be referred to as ‘integral’ of the differential equation, the word
being coined by James Bernoulli (1654 - 1705) in 1690 The word ‘solution was
first used by Joseph Louis Lagrange (1736 - 1813) in 1774, which was almost
hundred years since the birth of differential equations It was Jules Henri Poincare
(1854 - 1912) who strongly advocated the use of the word ‘solution’ and thus the
word ‘solution’ has found its deserved place in modern terminology