## anonymous 5 years ago is this a function?

1. anonymous

no

2. anonymous

haha sorry i still need to attach the file!

3. anonymous

A function need to pass a verticle line test

4. anonymous

i know but i cant tell if this one does.. i graph it on my calculator but its not working

5. anonymous

You calculator will only graph the top half

6. anonymous

Plot a second function with - infront of it

7. anonymous

http://www.wolframalpha.com/input/?i=Plot%5B {Sqrt%5B%28x%2B2%29%2F2%5D%2C-Sqrt%5B%28x%2B2%29%2F2%5D}%5D

8. anonymous

I posted the link to my plot, can you see it?

9. anonymous

is $\sqrt{x}-1$ a function

10. anonymous

Yes

11. anonymous

http://www.wolframalpha.com/input/?i=Plot%5B {Sqrt%5B%28x%2B2%29%2F2%5D%2C-Sqrt%5B%28x%2B2%29%2F2%5D}%5D

12. anonymous

ok. the link is only partly blue so i dont think its working

13. anonymous

14. anonymous

okay now i see it!! but i still cant tell if it is a function. is it?

15. anonymous

It is not since it does not pass the verticle line test. Blue(top) and purple plot(bottom)

16. anonymous

My two cent. If a teacher gives you a function, as a equation than it is probably a function. If the teacher graphs it for you than it is probably NOT a function, but in both cases you need to verify it with the vertical line test. It is extremely hard to make an equation that is not a function.

17. anonymous

y = +- sqrt x is not a function

18. anonymous

its +- sqrt x -1 though

19. anonymous

well its the same idea

20. anonymous

so for sure it is not a function? also, what is the domain of 3x^2+4x+2? os ot a;; real numbers

21. anonymous

is it all real numbers**

22. anonymous

all real numbers, because there is no reason to restrict the domain

23. anonymous

for example y = 1/x , we cant have division by zero when x = 0, so x=0 is not in the domain. but the rest of real numbers is

24. anonymous

okay, so is $\sqrt{x}-1$ a function or not??? i need a final answer!!!!!!

25. anonymous

its a function, but when you have +- , it isn't a function

26. anonymous

is 5/9 (F-32) a function