A.8 Direct & Inverse Variation

Graph of a Direct Variation

A line that goes through the origin

Graph of an Inverse Variation

Two curves that never cross the x-axis or y-axis

How to check if a table represents an Inverse Variation:

check if xy is constant for each pair

How to check if a table represents a Direct Variation:

check if y/x is constant for each pair

Inverse Variation Constant (k)

k=xy

Direct Variation Constant (k)

k=y/x

In an Inverse Variation, as one variable increases...

the other variable decreases

In a Direct Variation, as one variable increases...

the other variable increases

Inverse Variation equation

y=k/x

Direct Variation equation

y=kx