Question

What is the domain of the following graph?

Answer 1

Is it {x|x E N}

or {x|x E R}

Answer 2

hint: domain is the set of allowed inputs or x values

Answer 3

Yeah I know but I'm not sure what the letter symbols mean.

Answer 4

x E N means x is a natural number

x E R means x is a real number

Answer 5

natural numbers are:

1, 2, 3, 4, 5, 6, 7, 8, 9, ....

Answer 6

I woud believe that It'd be all real numbers since there happens to be negative numbers for the graph.

Answer 7

so a number like x = 5 is part of the domain?

Answer 8

I dont think so since the end points of the circle reaches out to 5 on the horizontal line which would be x.

Answer 9

It doesnt i mean.

Answer 10

what is the smallest x value that's part of the graph?

what is the largest x value that's part of the graph?

Answer 11

smallest would be -4 and largest 4.

Answer 12

so the domain is

\[\large -4 \le x \le 4\]

Answer 13

in interval notation, the domain is [-4, 4]

Answer 14

Ahh I see but when you put that on a graphing calculator the inequality doest make a circle at all it shades from -4 to positive 4 is that what its supposed to do?

Answer 15

that inequality just restricts what x values are allowed (and which aren't allowed)

it doesn't actually graph the circle

Answer 16

Ohh see that is what totally confused me, I figured that it would graph the circle. It just shades the region that the circle covers from. Now I get it. Thanks!

Answer 17

yes exactly, and yw