Suppose that the exponential growth function is y = 4^x.
If x = 1, then y = 4^1 = 4.
If x = 3, then y = 4^3 = 64.
Let the initial value be 1/2.
The growth function is now y = 1/2 * 4^x.
If x =1, then y = 2 which is half of the y value before adding the 1/2.
If x = 3, then y = 1/2 * 64 = 32.
Answer: 1/2
