For which value of does the function represent an exponential decay function?

MATHEMATICS · Single correct · AP · AP Precalculus · Exponential and Logarithmic Functions · Exponential and Logarithmic Functions

Problem

For which value of

k

does the function

f(x)=5\,k^{x}

represent an exponential decay function? (a)

k=-2

(b)

k=1

(c)

k=\dfrac13

(d)

k=\dfrac32