How do you tell whether #f(x)=-(6/5)^-x# is an exponential growth or decay?

1 Answer
Jun 24, 2017

exponential decay

Explanation:

To figure out whether a function represents exponential growth or decay, we must put it in the form #f(x) = a*b^x#.

#-x# is equal to #-1 * x#, so the function becomes

#f(x) = -(6/5)^(-1*x)#

Since we know that #(a/b)^-1# is equal to #(b/a)#, we can rewrite the function in the form that we want.

#f(x) = -(5/6)^x#
or #f(x) = -1(5/6)^x#

If #0 < b < 1#, then the function represents exponential decay.
If #b > 1#, then the function represents exponential growth.

In our case, #0 < 5/6 < 1#, so this is exponential decay.