Question

Which is a stretch of an exponential decay function? f(x) = Four-fifths (five-fourths) Superscript x f(x) = Four-fifths (four-fifths) Superscript x f(x) = Five-fourths (four-fifths) Superscript x f(x) = Five-fourths (five-fourths) Superscript x

Answer 1

2

Explanation:

B

Answer 2

Options 2 and 3 are correct.

Explanation:

The general form of an exponential decay function is
`f(x) = a(b)^(x)` where b < 1.

Now, the four exponential functions are:

(i)
`f(x) = (4)/(5)((5)/(4) )^(x)` is not an exponential decay function as
`(5)/(4) > 1`.

(ii)
`f(x) = (4)/(5)((4)/(5) )^(x)` is an exponential decay function as
`(4)/(5) < 1`.

(iii)
`f(x) = (5)/(4)((4)/(5) )^(x)` is an exponential decay function as
`(4)/(5) < 1`.

(iv)
`f(x) = (5)/(4)((5)/(4) )^(x)` is not an exponential decay function as
`(5)/(4) > 1`.

So, options 2 and 3 are correct. (Answer)