Question

How do you find the domain of a function?

Answer 1

I have this problem,
Is this a calculator type question?

Answer 2

yes it is a calculus and algebraic problem type of question

Answer 3

& I'm clueless as to what this symbol is

Answer 4

I meant is this a qeustion that I should solve on a calculator or by hand?

Answer 5

finding the domains in simple words with no abbreviations means what values can i plug in x which gives me a justified y.

Answer 6

in other words what values of x satisfies y

Answer 7

The - 2?

Answer 8

the function above excepts values (-inf, +inf)

Answer 9

all sorts of values fit

Answer 10

let me illustrate the point by giving you an example

Answer 11

accepts*

Answer 12

not excepts...

Answer 13

Alright,

Answer 14

in other words a domain is how is your function behaving according to the values of x

Answer 15

example:

Answer 16

what is the domain?\[y = \sqrt{x}\]

Answer 17

if you plug in -1 \[y = \sqrt{-1}\]

Answer 18

The domain is being squared, is that what you mean?

Answer 19

this -1 violates y

Answer 20

all the x must be greater or equal to zero

Answer 21

so the answer would be [0, inft)

Answer 22

or \[x \ge 0\]

Answer 23

so any number that is greater or equal to zero will be accepted

Answer 24

because root of -1 is undefined

Answer 25

Ah I'm confused, I dont get how you get 0 & infinity?

Answer 26

yes that is why i am trying to tell you the concept of what a domain is

Answer 27

if y=x then you can use values from -inf to inf

Answer 28

so the domain would be (-inf, +inf)

Answer 29

But how did the 0 come in?

Answer 30

but there are functions if you put some values for x it will be undefined

Answer 31

because root of 0 is 0 so we don't have a problem

Answer 32

i can include the zero in the root

Answer 33

but if you have a function y=1/x, it will be x accepts all values apart from zero

Answer 34

because 1/0=inf

Answer 35

But theres not a 0 in the problem, I dont get what happens to the -2x & the 4

Answer 36

the best way is to draw a function and see how x values bahave

Answer 37

let me draw you the function