Question

Which best describes the exponential function f(x)=(0.9)x?

Answer
a.
f(x) is a decay function with a rate of 90%.
b.
f(x) is a growth function with a rate of 90%.
c.
f(x) is a decay function with a rate of 10%.
d.
f(x) is a growth function with a rate of 10%.

Answer 1

remember that exponential decay functions look like:

\[y = a(1 - r)^{x}\]

where r is the rate of decay

Answer 2

so if something, like in your case, is 90% of its previous value, then the next is 90% of that. what is the rate of decay?

Answer 3

Wouldn't be 90%?

Answer 4

like if i start with 100 atoms ( just say) and it decays into 90 atoms, then that decays into 81 atoms, etc. i have 90% of the previous value. but that is not a 90% rate of decay, it would only be a 10% rate of decay since i'm losing 10% each time

Answer 5

Oh. I see now. So it would be A correct?

Answer 6

c looks right because the rate of decay is 1 - 0.90

Answer 7

*Face Palm.