分部积分法怎么做，求过程
\u7528\u5206\u90e8\u79ef\u5206\u6cd5\u505a\uff0c\u600e\u4e48\u505a\uff0c\u8bb2\u4e00\u4e0b\u8fc7\u7a0b=-2e^(-2x)*cos(x/2)+2∫cos(x/2)*-2e^(-2x)dx
=-2e^(-2x)*cos(x/2)-8∫e^(-2x)d[sin(x/2)]
=-2e^(-2x)*(cos(x/2)+4sin(x/2))+8*∫sin(x/2)*-2e^(-2x)dx
=-2e^(-2x)*(cos(x/2)+4sin(x/2))-16*∫e^(-2x)*sin(x/2)dx
所以原式=-2/17*e^(-2x)*(cos(x/2)+4sin(x/2))+C
学过已经忘了，只记得书上其实都有步骤和例题，看了应该就会
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