跪求f（x）=2-（x分之3）limx*sin(1/x) ∩｛P丨PA=PC}(a-b)/sin(a-b)

Question

跪求f（x）=2-（x分之3）limx*sin(1/x)
∩｛P丨PA=PC}(a-b)/sin(a-b)

Answer 1

x=1 rcosA,y=-1 rsinA,r>0,Aax*2 bx c=0中 -ac<0 仿照|ax b|0)仿照x=1 rcosA,y=-1 rsinA,r>0,A