Question

How in the world do I do this?

Answer 1

my neck hurts :(

Answer 2

\[\{(x,y):y=x^2\}\]the definition of the Domain is the set of all x values for which y is defined (i.e. all the values of x that you can plug into \(y=x^2\) without getting division by zero, the square root of a negative number, the logarithm of a number less-than or equal-to zero, or something like that

Answer 3

are there any values of x that you could put into that formula that would not be defined? if so, what are they?

Answer 4

Words dont help me. Im a visual learner.

Answer 5

well this "image" would be infinitely large to demonstrate the concept of this particular domain, so I'm afraid that's not really an option, though a picture may help....

Answer 6

Im sorry, but when i try and read all them words. i get even more confused.

Answer 7

http://www.wolframalpha.com/input/?i=plot%20y%3Dx%5E2&t=crmtb01

^here is your image
the domain is all the x's that are allowed in this function
is there some x where the graph has no y value?

Answer 8

I dont even understand the answers.

Answer 9

Im sorry. Math just isnt my subject.

Answer 10

I can explain the notation better when you comprehend what I'm trying to say...
if I put in x=1 to y=x^2 I get y=1
if I put x=-1 I again get y=1
if I put x=0 I get y=0
if I put x=100 I get y=10000

is there \(any\) x you can think of that will not give you back a y value?

Answer 11

how about this one:
what is the domain of \[y=\frac1x\]?
(what value(s) of x will cause y to be undefined?)

Answer 12

if I tell you that the above is undefined for x=0 would that make sense to you?

Answer 13

Im confused. lol

Answer 14

say we have\[y=\frac1x\]and I wanna know what y= when x=0
what do we get?
plug in x=0 and...\[y=\frac10=\text{undefined}\]why?
because division by zero is a no-no, which you should probably have learnt by now.
so the domain of this function would be \[\{x:x\in\mathbb R,x\neq0\}\]that notation means
"the domain of the function is the set of all real numbers \(\mathbb R\), except x=0"

Answer 15

so the domain asks "what numbers are "allowed" for x

Answer 16

Ok i have a question. For a set of numbers to be a function. which can have the same numbers. x or y?

Answer 17

the definition of a function is that for each x, there is exactly one y associated with it
if when x=1, we have y=2 and y=-2, then it is not a funtion because one x corresponds to more than one y

however y=0 for example, is a function, because for each x there is only one y-value; namely y=0

Answer 18

So if i had (1,3)(2,3)(3,4) would that be a function? which ones cant be the same x or y?

Answer 19

an x cannot have two different y's