Differential equations first appeared in the late seventeenth century in the work of Isaac Newton, Gottfried Wilhelm Leibniz, and the Bernoulli
brothers, Jakob and Johann. They occurred as a natural consequence of the efforts of these great scientists to apply the new ideas of the calculus to
certain problems in mechanics, such as the paths of motion of celestial bodies and the brachistochrone problem, which asks along which path from
point Ρ to point Q a frictionless object would descend in the least time. For over 300 years, differential equations have served as an essential tool
for describing and analyzing problems in many scientific disciplines.