π2arctanxx的极限rct-887婚纱，x趋向于无穷时rct-887婚纱，不用洛必达，用等价无穷小，π2arctπ2arctanxx的极限，x趋向于无穷时，不用洛必达，用等价无穷小，π2arctanx等价于tanπ2arctanx，然后该怎么解rct-887婚纱？π2arctanxx的极限，x趋向于无穷...