Investigation 5: Exploring Exponential Functions

Test yourself

1. 

   Based on the graph the value of a would be 2, since it is the y-intercept of the graph. Since it is a decay curve (decreases from left to right), then b < 0 . The asymptote is the x-axis or the line with equation y = 0 .

2. The y-intercept is always the value of a in the equation and the function is a
   growth function if b > 0 and a decay function is b < 0. Thus:

   (a) y = 0.5 (2.5)^x y-intercept is 0.5 and it is a growth function

   (b) y = 2.5 (0.5)^x y-intercept is 2.5 and it is a decay function.