Is this function continuous $$f(x)=+\sqrt{x-3}$$?
See development and solution
Development:
Radical functions are continuous within their domain. In this case
$$$x-3 \geq 0$$$ $$$x\geq3$$$ $$$\Rightarrow D(f_x)=[3,+\infty)$$$
Solution:
Therefore $$f(x)$$ is continuous in $$[3,+\infty)$$.