- #1
JazzMasterKC
- 19
- 0
Homework Statement
A table is given:
x | -2 | -1 | 0 | 1 | 2 | 3
h(x) | 0 | 9 | y | 3 | 0 | 6
Well actually the h(x) line was based on a graph that we had to look at, it should be right. I discovered y = 8 (the graph increments by 3 on y-axis and 1 on x axis, so I couldn't tell what y was)
so d = 8, b = -2
This graph is a cubic function, so I'm using ax^3+bx^2+cx+d formula
I got c=-8 and a=2
The first question that I got was to fill the h(x) part of table (thats all the direction I had)
Then the second part of the question was to figure h(3)-h(1).. ok yeah no problem easy enough..
However here is the catch.. using the found equation from my data.. well first this is what it is:
y=2x^3-2x^2-8x+8
.. so anyways I graphed in calculator and when I look at the table I noticed for x=-1 y=12.. which from viewing the graph its obvious that is false, The highest point on y-axis appears to be 10 at most from looking at graph... This has thrown me off and I'm not sure what to do now.. its clear I screwed up some where.
Homework Equations
my results for equation (wrong) y=2x^3-2x^2-8x+8
cubic form: ax^3+bx^2+cx+d
Here are the four equations I derived out of the data to get what I thought was my answer..
-8a+4b-2c+d=0
-a+b-c+0=9
a+b+c+d=3
8a+4b+2c+d=0
The Attempt at a Solution
I wish to evaluate h(3)-h(1) but I've noticed some errors with what I did in part 1 of the question.