Write the rule that represents the function
x = -1, 0, 1, 2
y = 1/4, 1, 4, 16
There are infinitely many rules that would represent that,
but the most obvious one is
because , , ,
But don't allow your teacher to tell you that is the ONLY one!
For we can always find a nth-degree polynomial that will go through
any n-1 points.
For instance this answer
is just as good, although
not quite as simple:
Substitute those x-values in that and you will also get the y-values.
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Write the rule that represents the function
x = 0, 1, 2, 3, 4
y = -7, -2, 3, 8, 13
We notice that
-7+5=-2, -2+5=3, 3+5=8, 8+5=13
So we suspect that this is linear, of the form y=mx+b
So we try
y=mx+b
Substitute (0,-7)
-7=m(0)+b
-7=b
So y=mx-7
Substitute (1,-2)
-2=m(1)-7
-2=m-7
5=m
so the obvious answer is y=5x-7
and if you substitute all those s-values you'll get
the corresponding y-values.
But there are many other functions that work too.
Edwin