Question

how to determine domain of y=log(4-x^2)

Answer 1

@phi @sourwing help please? i have an exam tomorrow ;_;

Answer 2

set 4- x^2 > 0

Answer 3

so is it x^2> +-2?

Answer 4

try again

Answer 5

I meant x> +-2, not x^2 :P

Answer 6

try again

Answer 7

it's a parabola that opens down. Where is it bigger than 0?

Answer 8

oh did I forget to flip the signs also? so will it be x<+-2

Answer 9

no, -2 < x < 2

Answer 10

I don't understand why?

Answer 11

but won't the parabola keep expanding both directions? so I don't understand how you can restrict x to -2<x<2?

Answer 12

-2 < x < 2 is where the parabola above the y-axis (i.e greater than 0)

Answer 13

look at the graph again

Answer 14

oh I see... ok

Answer 15

thanks