2. (17 points) Find the smallest root of the equation

$$
\sin (\pi x)+\tan x=x+x^{3}
$$
Answer: 0

Solution. Obviously, 0 is a root of the equation (when $x=0$, both sides of the equation are equal to zero). If $x<0$, the right side of the equation is negative, while the left side of the equation is always non-negative.