lim(x趋向于0)(cosx)^[1/(xsinx)]=lim(x趋向于0)[(1+cosx-1)^(1/(cosx-1))]^[(cosx-1)/(xsinx)] =lim(x趋向于0)e^[(cosx-1)/(xsinx)] =e^lim(x趋向于0)[(cosx-1)/(xsinx)] =e^lim(x趋向于0)[-sinx/(x+xcosx)] =e^(-0.5)
