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 The name of
the ‘method of separation of variables’ is due to John Bernoulli (1667 - 1748),
a younger brother of James Bernoulli Application to geometric problems were also considered It was again John
Bernoulli who first brought into light the intricate nature of differential equations