for x0
f(x) = x - sin1
lim(x->0+)f(x) = -sin1
lim(x->0-)f(x) = sin1 ≠ lim(x->0+)f(x)
f(x) is discontinuos at x=0
不能说明f(0) 使函数在x=0处连续
for x0
f(x) = x - sin1
lim(x->0+)f(x) = -sin1
lim(x->0-)f(x) = sin1 ≠ lim(x->0+)f(x)
f(x) is discontinuos at x=0
不能说明f(0) 使函数在x=0处连续