We can calculate the rate of change as the slope between two points, like (1,2) and (2,4).
The slope is:
[tex]m=\frac{y_2-y_1}{x_2-x_1}=\frac{4-2}{2-1}=\frac{2}{1}=2[/tex]If this is a linear function, this slope m has to be constant.
We will calculate the slope between other points, like (3,8) and (4,16):
[tex]m=\frac{y_4-y_3}{x_4-x_3}=\frac{16-8}{4-3}=\frac{8}{1}=8[/tex]The slope is not constant, so this function is not a linear function.
If we look at how f(x) increases, we can prove that f(x) is:
[tex]f(x)=2^x[/tex]and this function is an exponential function.
Answer: Option B (exponential function).
