## anonymous 5 years ago Can anyone help me with domain of a function

1. Owlfred

Hoot! You just asked your first question! Hang tight while I find people to answer it for you. You can thank people who give you good answers by clicking the 'Good Answer' button on the right!

2. anonymous

what do u need help w/? like what it is or how to rite one?

3. anonymous

domain is the inverse range divided by three halves

4. anonymous

okay, thanks for the answer, but what you just said asd24312 is over my head

5. anonymous

to jadegirl390 I need to know how to find the domain of a function. Not the range, just the domain

6. anonymous

the domain is the range divided by -1 quantity divided by three halves. Its the quickest way and makes the most sense

7. anonymous

oh forget it, i have no idea what that is. im thinking domain as in piecewise functions sry wifeofD

8. anonymous

I have never had algebra before in my life, so I really need help to understand. In plain English instead of math speak.

9. anonymous

aww thats cute

10. anonymous

??

asd... What? That's absolutely not always the relation of domain and range. Wifeofd -- the domain of a function depends on the function. Do you have any examples we can work through?

12. anonymous

In essence, the domain of a function is the set of values that x can take on in that function. So in $$y = x^2$$, x can be any real number, since you can plug any real number into that equation and get a y value out. In the function $$y = \sqrt{x}$$, however, x has to be positive, because the square root of a negative number is not a real number. Thus, in this case, the domain is $$x > 0$$.

14. anonymous

I barely passed pre-algebra with a D- and the college threw me into algebra and I don't understand anything. I feel so stupid.

$p(x) = x^2 - 2x + 5$ That's your function. Basically, ask yourself if there's any value of x that will break' that function, i.e., can you put in a value where $$x^2$$ doesn't work? Where $$2x$$ doesn't work?

16. anonymous

not sure. I am drawing a blank. Told you I was stupid.

17. anonymous

so ur asking what i thought, sry. so basically this is how my teacher taught us: if someone were to draw a picture of something on a graph using functions and all you wouldn't want the functions to go on forever, rite? so basically the domain the where you want the function to be. the x values that you want the equation to go through. does that help anything?

Hehe. No worries. This stuff can be tough at times. We can break it down a bit with a couple of facts. The domain of $$x^2$$, as we said above, is basically any number. The domain of $$2x$$, or indeed of $$ax$$ for any number $$a$$, is also any number. So, there is no restriction on the domain of $$p(x)$$. How you express that depends on what notation your book uses. The set notation way to say it is: $$x \in (-\infty, \infty)$$; this means that x can take on any value between negative infinity and positive infinity, i.e. any number. Or, you can say $$x \in \mathbb{R}$$, meaning that x is any real number..

19. anonymous

shadowfiend and jadegirl--??? I am so lost and confused, I am so sorry. I don't mean to waste your time. I just don't understand. I know that y'all are trying to help, I don't think there is anyone that can help me.

It's okay. The moment when it makes sense is just around the corner :) What I'm kind of limited by right now is that we can't draw anything on OpenStudy, but since I'm one of the people who builds this site, it's my fault :p Basically, the function you're asking about works for every value of x, and that is its domain. If a function doesn't work' -- for example, the square root of a negative number `doesn't work' -- then the domain cannot include those numbers for x.

21. anonymous

I am just too stupid in Math. I have no problems with the other subjects, it is just Math that I am left way far behind.

22. anonymous

what is a square root?? See, I am dumb as a box of rocks.

23. anonymous

kk so here would be my first advice (and i i dont want to sound cheesy and all) but just say that u cud figure this out. so basically here goes: a function is like a candy machine (u know what that is ;) if u push the buttton for coke only coke will come out, not grape soda or the like. (or at least it should) that is the same thing like a function, its like saying when y is # then x is only going to be a number and it'll never be another number. is that clear so far?

24. anonymous

25. anonymous

I am following

26. anonymous

kk sry i was just doing hw. a line, goes on forever, rite?

27. anonymous

one sec i brb

28. anonymous

I am doing hw myself so I know where you are coming from.

29. anonymous

kk so basically not necessarily can any number be an answer, for example square roots so a square root is the opposite of a square, does that make sense? meaning when u square a number, like 2, so that means you are saying 2*2 so a square root is the opposite of that. its giving u the answer and asking u for the number

30. anonymous

does that make sense?

31. anonymous

tell me if it doesn't. im just gonna cont. so basically you can never have a negative square root. i think so that means that (if that is true) that any number that would make that equation has to be a positive number. therefore the only x values (which is another word for domain) have to be positve. is that clearer?

32. anonymous

now that is throwing me off. the problem in my book doesn't include square roots

33. anonymous

In the problem that i put up, I changed the numbers, but it is set up the same way.

34. anonymous

sry didnt see the problem so is that basically in the book written p(x)=x to the second power subtract 2x add 5 p(x)=x^2 (that means raised to the nth pwr)-2x+5? what r u supposed to do with it?

35. anonymous

Find the domain of p

36. anonymous

hmmmm is there a graph with the equation?

37. anonymous

no, there are multiple choice answers though

38. anonymous

ok what r the options? i don't quite understand what they're asking. (is this algebra 1 or 2?) if u look at the back of ur book if this is an odd question they might have the answer, cuz mine does.

39. anonymous

I think it is algebra 1

40. anonymous

My book doesn't have the answer, unfortunately.

41. anonymous

The first day of class, my teacher confiscated the answer chapter in the book.

42. anonymous

from everyone in the class....

43. anonymous

thats a bummer, oh if u go on classzone.com and type in ur school code (u might have to get it from a teacher or idk ) they have the book online so they might have the answer. but if not, so what are the multiple choice things?

44. anonymous

a) x/x is a real number b) x/x is a real number and x is greater than 0 c) x/x is a real number and not equal to 10 d) x/x is a real number and not equal to 0

45. anonymous

i really wish i cud help more but i have no idea what to do, where even to start (so dont feel stupid :)) i cud ask my teacher if the hw isnt due tom. sry!!!!!!!!!!!!!!!!

46. anonymous

Unfortunately it is due to be scanned and emailed in by midnight tonight. thanks anyway for trying

47. anonymous

ahhhhhhhhhhhhhh gluck!!!!!!!!!!!!!!!!!!

48. anonymous

I don't feel stupid really, I know I am stupid.

49. anonymous

wai ti just thought of something. so a doesn't make sense (unlss the book is trying to trick u ) because all the other choices r real numbers too

50. anonymous

is there another equation on top of this one?