Some Examples of Ordinary Differential Equations with Missing x or y
This Demonstration solves ordinary differential equations of the forms and by introducing a new variable .[more]
In the first case, the procedure is as follows: , , , .
In the second case: , , , . In both cases a solution is given in parametric form: , .[less]
 L. E. Eljsgoljc, Differential Equations and Variational Calculus (in Russian), Moscow: Nauka, 1969 pp. 69–71.