Question

Which functions are exponential decay functions?
Choose exactly two answers that are correct.

Answer 1

f(x)=0.9^x
g(x)=(6/5)^x
h(x)=1.25^x
j(x)=(4/5)^x

Answer 2

Can you tell me what exponential decay is?

Answer 3

No. I mean I guess I could look it up in the dictionary, but at the top of my head; no.

Answer 4

Okay then let's think about this from another approach, do you know what an exponential function is? If something increases exponentially, what happens to y as x increases by a certain amount each time.

Answer 5

OK...

Answer 6

The second sentence was meant to be a question (missed off the question mark though, sorry!).

Answer 7

That is a question that I cannot answer. ;)

Answer 8

lol okay, sounds like someone wasn't paying attention in their maths lesson! We're looking for a function that vaguely resembles this

Now, let's have a think about your functions:

f(x)=0.9^x
f(1)=0.9
f(2)=0.81
f(3)=0.729

g(x)=(6/5)^x
g(1)=1.2
g(2)=1.44
g(3)=1.728

h(x)=1.25^x
h(1)=1.25
h(2)=1.5625
h(3)=1.953125

j(x)=(4/5)^x
j(1)=0.8
j(2)=0.64
j(3)=0.512

What can you see about these functions as x increases?

Answer 9

@tom982 Hold on, It might take me a minute to figure this out. Also technically I didn't even go to my math class (It's online) I'm in the process of moving and my computer had to be shipped back to my school and I have a ton of other issues going on. :)

Answer 10

I think it's D.

Answer 11

I understand, well if you get stuck with any of your other things feel free to shoot me a message and I'll do my best to explain.

D is correct, but why? What's happening with j(x) as x increases?

Answer 12

There's suppose to be one more but I don't know which. @tom982

Answer 13

I know there is, we're getting close to that. Can you answer my previous questions?