Find the domain of the function algebraically: x^2+4

Question

saifoo.khan · Answer

Satellliiteeee.

anonymous · Answer

if you see any polynomial you always say
"all real numbers"

anonymous · Answer

saifoooooooooooooooo!

amistre64 · Answer

lim[x to inf] perhaps?

anonymous · Answer

real

amistre64 · Answer

proof by induction?

anonymous · Answer

@amistre ???

amistre64 · Answer

how do you find a domain?  much less algebraically?

anonymous · Answer

well plug in every single x value and see for ur self

anonymous · Answer

HEHEHE

amistre64 · Answer

i thought of that, i did :)

anonymous · Answer

you do not "find" a domain it is supposed to come with the definition of the function.  let f(x) = expression on the domain "set"

anonymous · Answer

or see what is the graph restricted by

anonymous · Answer

my book says the answer is [-5,5] by [-5,15], i just dont know how to show my work

amistre64 · Answer

weve been getting alot of "find the domain" questions and im like .... how

anonymous · Answer

but the question really means "what is the largest set of numbers on which this function can act?"

anonymous · Answer

@madi 
hold the phone!  you book says what exactly for the domain?

amistre64 · Answer

i was pretty sure it was a built in part of the function :)

myininaya · Answer

are you sure thats the question?
and 
are you sure thats what your book says?

anonymous · Answer

maybe it is defining the domain?

amistre64 · Answer

check the back inside cover; does it say "made in china"?

myininaya · Answer

does it say made by amistre?

amistre64 · Answer

lol .....

anonymous · Answer

says made by mad math teacher

myininaya · Answer

if it says made by myininaya its okay

anonymous · Answer

it says "find the domain of the fumction algebraically and support your answer graphically". the question is f(x)=x^2 + 4

anonymous · Answer

ok for sure the domain is all real numbers.  this is not an "algebra" question.

amistre64 · Answer

by find; does it mean look up the function and fit it to a certain group with the given properties?

anonymous · Answer

it's an AP precal book

myininaya · Answer

so maybe its want a viewing window for the function that's why it gave those intervals in the back of the book
i don't know

myininaya · Answer

but any polynomial is continuous everywhere

amistre64 · Answer

x^2 + 4 is a child of the function: x^2 that has the property that its domain is the set of reals

anonymous · Answer

domain all real numbers, range $$[4,\infty)$$ here is a picture http://www.wolframalpha.com/input/?i=y%3Dx^2%2B4

myininaya · Answer

i like the word child

amistre64 · Answer

dance teacher said wed be doing something with "war dance" and i asked what she meant by "word ants"  lol

anonymous · Answer

thanks you guys