What is the correct notation for a function that has any given input value equal to its output value?
A.
f(x) = f(x)
B.
f(x) = x
C.
f(x) = –x
D.
f(x) = 1

Question

What is the correct notation for a function that has any given input value equal to its output value?
A.
f(x) = f(x)
B.
f(x) = x
C.
f(x) = –x
D.
f(x) = 1

whpalmer4 · Answer

Well, one of those functions always returns 1.  That must not be it.  Another one gives the opposite sign of the input, so that must not be it.  If you think of the f(x) = <something> as a recipe, which answer would you choose?

anonymous · Answer

d?

anonymous · Answer

The answer is B. x is the number you put into the function f. f(x) is the result when you put in x. So f(x)=x means that the output when you input x into function f is equal to the input x

whpalmer4 · Answer

D is a recipe that says "whatever value of x you give me, the value of the function is 1".  Does that sound like a recipe for giving the input value?  C is a recipe that says "whatever value of x you give me, the value of the function is -x".  A is a recipe that says "whatever value of x you give me, the value of the function is the value of the function" — well, what the heck is the value of the function?  B is the one that says "the value of this function is the value of x you gave me" so B is the correct answer.

anonymous · Answer

mkay