Hi I have a limit with two variables in front of me and the book says directly that it is equal with $1$ but for the life of me I dont understand why?? maybe the answer is stupid but I am excausted and I can't see it! Here is the limit:

$$\lim\_{(x,y)\to(0,0)}(x^2+1)\cdot\frac{\sin y}{y}$$

Thanks in advance.