Question

How to determine if a table of values represents a linear, exponential or quadratic function?

Answer 1

Given x and y values...

Answer 2

if the first difference is constant, it's linear.
if the second difference is constant, it's quadratic.
if the difference repeat, it's exponential.

Answer 3

For an example, this is exponential. How would I know what equation it is?
x: -8, -4, 0, 4, 8
y: -1, 0, 1, 2, 3

Answer 4

it only comes from mostly ordered pairs and nothing else

Answer 5

sometimes equations but rarely

Answer 6

wait... are these the coordinates (or xy-pairs):
(-8,-1)
(-4,0)
(0,1)
(4,2)
(8,3)
is this correct?

Answer 7

because this relation is not exponential... for every 4 units movement on the x, there is a 1 unit movement on the y. this is linear...

Answer 8

and if you want the equation of this linear relation, choose any two points to find the slope then you can use any of the other points to put in point-slope form for the equation of a line.

Answer 9

@dpalnc So how would I know, given a set of coordinates, what type of function it is?
Also, what is the general function for exponential functions (not for this problem)??

Answer 10

For an example, Linear is y=mx+b; Exponentional = ? and Quadratic = Ax^2 + Bx + C. How would also know if a set of values is quadratic?

Answer 11

@Mani Jha Any ideas?

Answer 12

An exponential function is defined as:
\[y=e ^{x}\]

Answer 13

Just substitute the given values in the equation, and check whether it is satisfied

Answer 14

ok here's a linear example: