For a first-order linear differential equation \( \frac{dy}{dx} + P(x) y = Q(x) \), the integrating factor is \( \mu(x) = e^{\int P(x) \, dx} \). The integrating factor for \( e^{-\frac{2x}{\sqrt{x}}} \frac{dy}{dx} = 1 \) is \( \mu(x) = e^{-1/\sqrt{x}} \).