=∫拿粗sintde^t=sinte^t-∫含敏兄e^tdsint=sinte^t-∫谈袭costde^t=sinte^t-coste^t+∫e^tdcost=sinte^t-coste^t-∫sintde^t=e^t(sint-cost)/2+C=x(sinlnx-coslnx)/2+C
