sinθ=（m-3）/（m+5）,cosθ=(4-2m)/(m+5)根据平方关系sin²θ+cos²θ=1∴（m-3)²/（m+5)²+,(4-2m)²/(m+5)²=1∴m²-6m+9+16-16m+4m²=m²+10m+25m²-8m=0解得m=0或m=...