## Calculus (3rd Edition)

Since the first order differential equation is the equation that in which the highest derivative is equal to $1$, then (a) $y'=x^2$ , (c ) $\left(y^{\prime}\right)^{3}+y y^{\prime}=\sin x$ (d) $x^{2} y^{\prime}-e^{x} y=\sin y$ (f) $y y^{\prime}+x+y=0$ are first order differential equations.