Question 840481
You cannot take the square root of a negative number (and get a real numbered result). So that's why the radicand 2-x must be 0 or positive. So,


{{{2-x>=0}}}


{{{2>=0+x}}}


{{{2>=x}}}


{{{x<=2}}}


So the domain is the set of x values such that {{{x<=2}}}


In interval notation, the domain is <img src="http://latex.codecogs.com/gif.latex?\large&space;(-\infty,&space;2]" title="\large (-\infty, 2]" />