B:4-(x^2)≥04≥x^2x[-2,2]A:kx+(π/3)≤x＜kx+(π/2)画到数轴上看公共部分 f(x)=(x^2)cosa-4xsina+6>0cosa>0 b^2-4ac<0 解交集y=lg（tana-√3）/[√（x+10）*√(10-x)]x+10>0 10-x>0 √（x+10）*√(10-x)不等于0
