$$\lim_{x \to \infty}\left(\sqrt{x} + \sqrt{4 - x}\right) = \infty \operatorname{sign}{\left(1 + i \right)}$$
$$\lim_{x \to 0^-}\left(\sqrt{x} + \sqrt{4 - x}\right) = 2$$
More at x→0 from the left$$\lim_{x \to 0^+}\left(\sqrt{x} + \sqrt{4 - x}\right) = 2$$
More at x→0 from the right$$\lim_{x \to 1^-}\left(\sqrt{x} + \sqrt{4 - x}\right) = 1 + \sqrt{3}$$
More at x→1 from the left$$\lim_{x \to 1^+}\left(\sqrt{x} + \sqrt{4 - x}\right) = 1 + \sqrt{3}$$
More at x→1 from the right$$\lim_{x \to -\infty}\left(\sqrt{x} + \sqrt{4 - x}\right) = \infty \operatorname{sign}{\left(1 + i \right)}$$
More at x→-oo