Find the domain of the function and express the answer in interval notation: f(x)=sqrt(4x-16)

Question

anonymous · Answer

$$4x-16\geq 0$$
$$4x\geq 16$$
$$x\geq4$$

anonymous · Answer

because you cannot take the square root of a negative number

anonymous · Answer

i would take it that the answer to this question is (-$$\infty$$, 16)

anonymous · Answer

$$\sqrt{4x-16}\ge 0$$

anonymous · Answer

the answer is 
$$[4,\infty)$$

anonymous · Answer

satellite is rght

anonymous · Answer

the expression inside the radical must not be negative. that is why you solve 
$$4x-16\geq0$$ for x

anonymous · Answer

how would 4 be the answer, because i think i kinda figured out how to do this when its dividing.

anonymous · Answer

lets go slow

anonymous · Answer

this is 
$$f(x)=\sqrt{4x-16}$$ yes?

anonymous · Answer

and you have to worry about the radical, because you cannot take the square root of a negative number.

anonymous · Answer

it is not the same as problems with the variable in the denominator.  this time you worry about what is under the radical. it must not be negative. so we write 
$$4x-16\geq 0$$
add 16 to get
$$4x\geq16$$
divide by 4 to get
$$x\geq 4$$

anonymous · Answer

in interval notation it is 
$$[4,\infty)$$

anonymous · Answer

ok, i can see how you got that. i think that i just dont get how everything changes depending on how the problem is set up.