# How do you determine if the equation #y = 2.1(0.15)^x# represents exponential growth or decay?

##### 1 Answer

Apr 24, 2016

y decays as x increases..

#### Explanation:

Let

As x increases,,y is decreasing or increasing according as y' > or < 0.

For decay, y' < 0, when b > 0 and 0 < ln a < 1.#

Here,

So, y decays as x increases.