Thread: Finding a Quadratic Equation from Mulitple Points

I know their are quite a few of these questions on the net and I have looked at them, but I havent really been able to properly understand how they actually work.

I have to find what x when y=.11, so im guessing that I need to find the quadratic equation, right???
NOTE: Im not 100% sure this is a quadratic equation. If it isn't, any suggestions on how to solve it.

x y

0 16
1 8
2 4
3 2
4 1
5 0.5
6 0.25
7 0.125
8 0.0625

Hi,
It's not a quadratic function, it is rather .

Can I use this to solve my problem???

yes, take logarithm of both sides to express x:
, so .

I don't know what ".11" is, never seen it. Can you explain pls?

Sorry. Its part of a word problem where I have to find the age (in carbon-14 half lives) of a sample with a rate of disintergration of C-14 of .11 disintergrations/min/gram. I ve been given the first the first 3 numbers of each variable and I used Excel to copy the formula.

Half Life Disintergration rate
0 16
1 8
2 4
(Note 1 C-14 Half-Life = 5730 Years before present)