Chapter 7 - Exponential and Logarithmic Functions - 7-1 Exploring Exponential Models - Practice and Problem-Solving Exercises - Page 439: 25

Exponential Decay; $y$-intercept$=1$

Re-write the given function as: $f(x)=(2^{-1})^x=\left(\dfrac{1}{2}\right)^x$ We have: $a=1$ and $b=\dfrac{1}{2}$, which is less than $1$, which indicates that the function is exponential decay. The $y$-intercept is given by: $f(0)=2^{-0}=1$