Question

Without graphing, predict whether the function, y = 3(0.2)x, shows exponential growth or decay. Justify your predictions.

A. decay; because 0.2 < 1
B. growth; because 0.2 < 1
C. decay; because 0.2 > 1
D. growth; because 0.2 > 1

Answer 1

Hello,

Answer A

Let's choice x and x+1

x<x+1
==>
y1=3*0.2^x

y2=3*0.2^(x+1)

y2/y1=3*0.2^(x+1)/(3*0.2^x)=0.2

y2=0.2*y1<1*y1
The function shows a decay.