Unit 4 Target 2.1: Inverse Variation Functions
We have looked at Direct Variation Functions. But…are
there other functions we can find?
Look at the table below. Do you notice any patterns? Is
there a relationship between x and y? What about y and x?
Does the table represent a Direct Variation or something
else?
X
Y
5
20
10
10
25
4
What about the graph below?
Both the table and graph represent an Inverse Variation
Function. Let’s look closer.
Unit 4 Target 2.1
Inverse Variations
Finding a Missing Value in an Inverse Variation
The points (3,8) and (2,Y2) are two points in an inverse
variation. Find the missing value.
Steps
Work
Use the coordinate
equation.
Another way of writing this is y = __________
Substitute the values
Writing an Inverse Variation Function Given a Point
Simplify
Suppose y varies inversely with x and y = 7 when x = 5. Write
an equation for the inverse variation.
Steps
Work
Use inverse variation
equation.
Each pair of points is on the graph on an inverse variation. Find
the missing value.
Substitute the values
for x and y.
A. (3, Y1) and (5, 9)
Multiply to solve for
k (constant)
Write final equation.
Suppose y varies inversely with x. Write an equation for
the inverse variation.
A. Y = 6 when X = 3
Solve for missing
value
B. Y = 10 when X = 2.4
B. (75, 0.2) and (X1, 3)