When<u> 0<b<1 </u>, the graph shows <u>exponential decay</u>. In this case, b was equal to 1/2 as shown by the graph alongside the question. Therefore, the graph shows exponential decay.
The graph of y = 2^x would show a reflection of y = 1/2 ^x over the y-axis, therefore the graph shows <u>y = 2^x reflected over the y-axis</u>.