Question

What is the domain of the graph of y = -x2 + 6x + 11?
a: x ≤ 3
b: All real numbers
c: x ≤ -3
d: x ≥ 3

Answer 1

The domain is the set of all input values. So what values make this function defined?

Answer 2

c ?

Answer 3

is there any way that this function can be undefined

Answer 4

um...

Answer 5

ways of it becoming undefined... dividing by 0, ln(u) where u is <= 0,

Answer 6

i'm confused

Answer 7

A function is a specific set of rules that map values in a domain to values in a range. A function is like a special set of cooking rules that turn a pig into ham, or whatever you want to cook. So the pig is like the domain; it is the input. And ham is the range, or the output.

So back to this example, the question asks what are the input values of this function? What is the pig?

So the pig is usually defined as the set of all real number values that make the function defined. (Defined means it makes sense. For example, when you divide by zero, the equation is undefined, it does not make sense because we can't divide by zero.) So bottom line is, the domain for this function is all real numbers except for numbers that make the function undefined. Your challenge is to find out what those are.