## Calculus (3rd Edition)

(a) is separable, $$y'=f(y)g(x); \quad f(y)=9y^2, \quad g(x)=1/x.$$ (b) is separable, $$y'=f(y)g(x); \quad f(y)=e^{3y}, \quad g(x)=\sin x/\sqrt{4-x^2}.$$ (c) is not separable (notice the addition sign). (d) is separable, $$y'=f(y)g(x); \quad f(y)=9-y^2, \quad g(x)=1.$$