Question

Suppose f varies inversely with g and that f=28 when g=2. What is the value of f when g=7?

Answer 1

f=kg is direct variation

f=k/g is inverse variation.

Answer 2

so i divide 7/2?

Answer 3

You first plug in the given values for f and g and find k

Answer 4

k= 28 * 2= 56

Answer 5

?

Answer 6

Yes. So now we know that f = 56/g

Answer 7

So now you can find f when g = 7

Answer 8

oh ok thanks

i have one more question

Answer 9

Are you going to tell me what it is or should I try and guess?

Answer 10

Use the given graph of the function f to find the following values for f^(-1)

f−1(−4)=
2. f−1(−3)=

3. f−1(0)=

4. f−1(2)=

5. f−1(4)=

Answer 11

the ans to the previous question is 8

Answer 12

56/7=8

Answer 13

yep. good job

Answer 14

how do i find the inverse of the graph and then look up the f(x)

Answer 15

Do you see that (2,-4) is on that graph?

Answer 16

yes

Answer 17

In the inverse function all the ordered pairs are reversed. So (-4,2) is an ordered pair of f^(-1)(x)

Answer 18

Or, in other words:
\[f ^{-1}(-4)=2\]

Answer 19

oh ok

Answer 20

then f^-1 (3)=1

Answer 21

yes

Answer 22

what about 0 and 2

Answer 23

wait is f^-1(2)=0

Answer 24

It looks to me like f(-1.5)=0 Would you agree?

Answer 25

So the function f contains the ordered pair (-1.5,0) So
\[f ^{-1}(0)=-1.5\]

Answer 26

yes i agree with -1.5=0...i was wrong about f^-1(2)=0

Answer 27

On the graph is the ordered pair (-2.5,2) so
\[f ^{-1}(2)=-2.5\]

Answer 28

would you say f^-1(4)= -4

Answer 29

Is (-4,4) on the graph you posted?

Answer 30

nvm, i miscounted

Answer 31

-3.5,4 is there though right?

Answer 32

Yes.

Answer 33

thanks for the help

Answer 34

yw