I can't afford the Apostol calculus vol. 2 there's a printing mistake in my copy of Apostol and I'm not sure how to prove this:

let f(x,y)={xsin(1/y) if y doesn't equal 0

and f=0 if y=0

prove that the iterated limits are not equal and that the f(x,y)->0 as (x,y)->(0,0)