Let f(x)=[2 x^2+1] and g(x)= {2 x-3, x<0; 2 x+3, x ≥ 0}, where [t] is the greatest integer ≤ t. Then, in the open interval ( -1,1 ), the number of…

Let $\displaystyle f(x)=\left[2 x^2+1\right]$ and $\displaystyle g(x)=\left\{\begin{array}{ll}2 x-3, & x<0 \\ 2 x+3, & x \geq 0\end{array}\right.$, where $\displaystyle [t]$ is the greatest integer $\displaystyle \leq t$. Then, in the open interval ( $\displaystyle -1,1$ ), the number of points where $\displaystyle f o g$ is discontinuous is equal to \_\_\_\_.