Let $$f: R-\left\{\frac{-1}{2}\right\} \rightarrow R$$ be defined by $$f(x)=\frac{x-2}{2 x+1}$$. If $$\alpha$$ and $$\beta$$ satisfy the equation $$f(f(x))=-x$$, then $$4\left(\alpha^2+\beta^2\right)=$$

The domain of the real valued function $$f(x)=\sin \left(\log \left(\frac{\sqrt{4-x^2}}{1-x}\right)\right.$$ is

The range of the real valued function $$f(x)=\sqrt{\frac{x^2+2 x+8}{x^2+2 x+4}}$$ is

If $$f(x)=\sqrt{2-x^2}$$ and $$g(x)=\log (1-x)$$ are two real valued functions, then the domain of the function $$(f+g)(x)$$ is