what is the domain and range of y=x^2-1
also is it a function

Question

what is the domain and range of   y=x^2-1       
also is it a function

anonymous · Answer

can someone help i have a test tomorrow

anonymous · Answer

pleeeease

jim_thompson5910 · Answer

are you allowed to graph? ie use a graphing calculator?

anonymous · Answer

yeah

jim_thompson5910 · Answer

ok what kind of graphing calculator do you have?

anonymous · Answer

i dont have one with me

jim_thompson5910 · Answer

so it's currently at school?

jim_thompson5910 · Answer

For now, we can use an online graphing calculator

anonymous · Answer

yes

jim_thompson5910 · Answer

I like this one best https://www.desmos.com/calculator

jim_thompson5910 · Answer

type `x^2 - 1` into the box and hit enter

jim_thompson5910 · Answer

hopefully you'll see a curve pop up

anonymous · Answer

yes

jim_thompson5910 · Answer

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jim_thompson5910 · Answer

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jim_thompson5910 · Answer

the arrows indicate that the function stretches off in that direction forever

it turns out that you can plug in any real number for x, and get some result out for y = x^2 - 1

so that's why the domain is the set of all real numbers. It's visually shown by how it stretches on forever (zoom out and you'll see it not ending)

anonymous · Answer

what about the range I get confused on the range

jim_thompson5910 · Answer

the range would be the set of real numbers y such that $\Large y \ge -1$

whatever you plug into the function will be some number either equal to -1 or larger than -1. It will never go below y = -1

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