First-order linear equation and integrating factor (Linear in y: dy/dx + P(x)y = Q(x). Multiply by IF = exp(∫P dx) so left)

jee-mainjee-advanced

Linear in y: dy/dx + P(x)y = Q(x). Multiply by IF = exp(∫P dx) so left side becomes d/dx(y·IF); integrate to solve.

What each symbol means

SymbolWhat it stands for
IFIntegrating factor e^{∫P dx}.
P(x)Coefficient of y.
Q(x)Nonhomogeneous term.

When to use this

Standard form must have coefficient 1 on dy/dx (divide through if needed).