$a, b$ so $f(x)=x^2\sin(1/x+1), x>0$ $f(x)= ax+b, x \le 0$ becomes continuous at $x=0$

Question

$f(x)=x^2\sin(1/x+1), x>0$

$f(x)= ax+b, x \le 0$

I need to pick $a$ and $b$ so that $f(x)$ is continuous at $x=0$. I already found out that $b = 0$. My question is if there exists an explicit solution for $a$ or if any value for $a$ is possible.

Thanks in advance!