求极限limx→0[(x-sinx)/(x-tanx)]．
原式=limx→0[(1-cosx)/(1-sec2x)] =limx→0[(cosx-1)/tan2x] =limx→0[(cosx-1)/x2]•(x2/tan2x) =-(1/2)
求极限limx→0[(x-sinx)/(x-tanx)]．
原式=limx→0[(1-cosx)/(1-sec2x)] =limx→0[(cosx-1)/tan2x] =limx→0[(cosx-1)/x2]•(x2/tan2x) =-(1/2)
