If \( \mathrm{f}(\mathrm{x})=\left\{\begin{array}{cl}\frac{\sin (\mathrm{a}+2) \mathrm{x}+\sin \mathrm{x}}{\mathrm{x}} ;…

If \( \mathrm{f}(\mathrm{x})=\left\{\begin{array}{cl}\frac{\sin (\mathrm{a}+2) \mathrm{x}+\sin \mathrm{x}}{\mathrm{x}} ; & \mathrm{x}<0 \\ \mathrm{~b} & ; \mathrm{x}=0 \\ \frac{\left(\mathrm{x}+3 \mathrm{x}^{2}\right)^{1 / 3}-\mathrm{x}^{1 / 3}}{\mathrm{x}^{4 / 3}} ; & \mathrm{x}>0\end{array}\right. \)

is continuous at \( x=0 \), then \( a+2 b \) is equal to :

[JEE Main 2020, 9 Jan (Shift 1)]