math 2200 sample exam
\( e^{3x} \): \[ e^{3x} \frac{dy}{dx} + 3 e^{3x} y = 6x e^{3x} \] Recognize the left side as a derivative: \[ \frac{d}{dx} (e^{3x} y) = 6x e^{3x} \] Integrate both sides: \[ e^{3x} y = \int 6x e^{3x} dx + C \] Use integration by parts for \( \int x e^{3x} dx \): Let \( u = x \), \( dv = e^{