lim(x->0)x/sinx=?lim(x->∞)x*sin1/x=?

lim(x->0)x/sinx=?lim(x->∞)x*sin1/x=?

重要極限lim(x->0)sinx/x=1
lim(x->0)x/sinx=1 = lim(x->0)1/(sinx/x)=1/1=1
lim(x->∞)x*sin1/x
取t=1/x,則t->0
lim(x->∞)x*sin1/x=lim(t->0)sint/t=1