2. lim(x,y )→(0,0)
【Chia-Chung We】評論
Let x=r cos(x) and y=r sin(x)then lim(x,y )→(0,0) =limr→0{2r3cos(x)sin2(x)/r2} =limr→0{2r*cos(x)sin2(x)}= 0Answer : (C)