limx→π41−cot3x2−cot x−cot3 x=___
0
34
12
∞
limx→π41−cot3 x2−cot x−cot3 x=limx→π4(1−cot x)(1+cot x+cot2 x)(1−cot x)(cot2 x+cot x+2)=limx→π4(1+cot x+cot2 x)(cot2 x+cot x+2)=1+1+11+1+2=34