6.1 Definition
Equation involving derivatives.
6.2 Order & Degree
Order = highest derivative
Degree = power of highest derivative
6.3 First-Order Differential Equations
(a) Variable Separable
dydx=f(x)g(y)\frac{dy}{dx} = f(x)g(y)dxdy=f(x)g(y) ∫1g(y)dy=∫f(x)dx\
int \frac{1}{g(y)} dy = \int f(x) dx∫g(y)1dy=∫f(x)dx
(b) Linear Differential Equation
dydx+P(x)y=Q(x)\frac{dy}{dx} + P(x)y = Q(x)dxdy+P(x)y=Q(x)
Solution:
ye∫Pdx=∫Qe∫Pdxdx+Cy e^{\int P dx} = \int Q e^{\int P dx} dx +
Cye∫Pdx=∫Qe∫Pdxdx+C