求极限,当x趋向于0,lim(1-cosx/2)x/(tanx-sinx),

lim(x→0)[(1-cosx╱2)x╱(tanx-sinx)] =lim(x→0)[╱(tanx-sinx)] =lim(x→0)[(x╱8)╱{sinx(1-cosx)╱cosx}] =lim(x→0)[xcosx╱4sinx] =lim(x→0)[cosx╱4] =1╱4