sin(x+1080°)cos(x-360°)=2a+1.求实数a的取值范围
问题描述:
sin(x+1080°)cos(x-360°)=2a+1.求实数a的取值范围
答
sin(x+1080°)cos(x-360°)=sinxcosx=0.5sin2x=2a+1
-0.5≤2a+1≤0.5
-3/4≤a≤-1/4