Question

How do I multiply functions together? Lets say we get the graph of f(x) and f(g). What would the graph of "fg" look like?

Answer 1

same as you multiply normal numbers

Answer 2

can you give examples?

Answer 3

really depends on the functions doesn't it?

Answer 4

x^3 +3x -2
5x -2
----------------
5x^4 +15x^2 -10x
-2x^3 -6x +4
-------------------
5x^4 -2x^3 +15x^2 -6x -10x +4

Answer 5

f() = -1x
g() = sin(x)

Answer 6

i mean the graph part. you multiply by multiplying

Answer 7

-x sin(x) then

Answer 8

flips it over about the x axis

Answer 9

oooh -x not -1 sorry

Answer 10

sin(x) is stuck between 1 and -1 so -xsin(x) is stuck between the two lines y = x and y = -x

Answer 11

the graph of the sin is flipped annd is bounded by y=x line right?

Answer 12

very nice picture actually

Answer 13

y = x and y = -x.

Answer 14

http://www.wolframalpha.com/input/?i=y%3D-x*sin%28x%29

Answer 15

Alright then. Lets say you were given only a graph of 2 functions. How would you find out how the graph of fg look like then?

Answer 16

not so easy

Answer 17

That's one of the questions on my practice SAT 2 Math 2. Ugh...

Answer 18

just think of a simple example. you know what y = x looks like, you know what y = x^2 looks like, but from the two graphs how could you visualize y = x^3?

Answer 19

if f(x) = 3; and g(x) = 10; then id say h(x) = 30
if f(x) = 4; and g(x) = 5; then id say h(x) = 20
if f(x) = 1/2; and g(x) = 38; then id say h(x) = 19

Answer 20

you multiply the corresponding y values to get the resulting new value

Answer 21

^ That made everything so much more simple. Thanks!

Answer 22

:)