∫t*sint*dt=t*(-cost) - ∫(-cost)*dt=-t*cost + ∫cost*dt=-t*cost + sint + C 扩展资料:分部积分:(uv)'=u'v+uv' 得:u'v=(uv)'-uv' 两边积分得:∫ u'v dx=∫ (uv)...
求2tsint(cost)^2的定积分怎么做啊 - —— tsint/(1 + cost)=[(1 + cost)(tsint)' - tsint(1 + cost)']/(1 + cost)^2=[(1 + cost)(sint + tcost) + tsintsint]/(1 + cost)^2=[sint + costsint + tcost + tcostcost + tsintsint]/(1 + cost)^2=[sint(1 + cost) + t(cost + 1)]/(1 + cost)^2=(sint + t)(1 + cost)/(1 + cost)^2=(sint + t)/(1 + cost) 还要化简么???
请教如何解答?∫xcos(x/2)dx - —— 用分部积分 ∫xcos(x/2)dx=2∫xcos(x/2)d(x/2)=2∫xdsin(x/2)=2xsin(x/2)-2∫sin(x/2)dx=2xsin(x/2)-4∫sin(x/2)d(x/2)=2xsin(x/2)+4cos(x/2)+C