sinx-cosx=m1+2sinxcosx=m^2sin(2x) = m^2 - 1因为 sin(2x) 属于 [-1,1]所以 m^2 - 1 属于(-无穷大,-1)U(1,+无穷大)m^2>=0,m^2-1>=-1,因此 m^2 - 1 属于(1,+无穷大)m^2 属于 (2,+无穷大)m 属于 (-无穷大,-根号2)U(根...