大学极限题
以下4题,(1)(2) (3)只需要给个答案,(4)给个做法
(1)lim(x->3)(x^2-9)/(x-3)
(2)lim(x->3)(x^2-2)/(x-3)
(3)lim(x->2)(1/(x-2))-(4/(x^2-4))
(4)lim(x->0)(xsin(1/x)