(1)lim(sin2x-cos2x-1)/(cosx-sinx)
=lim{2sinxcosx-[2(cosx)^2-1]-1}/(cosx-sinx)
=lim2cosx(sinx-cosx)/(cosx-sinx)
=lim(-2)cosx (x趋向于π/4)
=-2^0.5
(2)x趋向于?
(1)lim(sin2x-cos2x-1)/(cosx-sinx)
=lim{2sinxcosx-[2(cosx)^2-1]-1}/(cosx-sinx)
=lim2cosx(sinx-cosx)/(cosx-sinx)
=lim(-2)cosx (x趋向于π/4)
=-2^0.5
(2)x趋向于?