∵sin(x+ π 4)＝35，sin(x− π 4)＝45，∴22(sin⁡x+cos⁡x)＝3522(sin⁡x−cos⁡x)＝45，两式相比得sin⁡x+cos⁡xsin⁡x−cos⁡x＝34，即4sinx+4cosx=3sinx-3cosx，∴sinx=-7cosx，∴tanx=-7...