Question 468408
Please help me find the domain to this function
sqrt(x^2-2x-8)
..
The expression inside a radical must always be ≥0
x^2-2x-8≥0
f(x)=(x-4)(x+2)≥0
If x≥4, f(x)≥0
If x≤2, f(x)≥0
If x<4, f(x)<0
If x>2, f(x)<0
Domain: (-&#8734;,2] U [4,&#8734;)