Als Beispiel sei die gravitative Wirkung der Venus auf die Erdbahn erwähnt.Von grosser praktischer Bedeutung, insbesondere für die Navigation auf See, war die Untersuchung des Einflusses der Sonne auf die Mondbewegung.
The Swiss mathematician Leonhard Euler (1707–83) studied the problems surrounding the moon's orbit throughout his life. The present work, published in Latin in 1753, is his triumphant solution, showing that Newton's laws were sufficient to explain lunar motion.
In the first book, since all of analysis is concerned with variable quantities and functions of such variables, I have given full treatment to functions. I have also treated the transformation of functions and functions as the sum of infinite series.