Question

On a coordinate plane, an exponential function approaches y = 0 in quadrant 2 and increases into quadrant 1. It goes through (negative 1, 0.25), (0, 0.5), (1, 1).
Which exponential function is represented by the graph?

f(x) = 2(one-half) Superscript x
f(x) = One-half(2)x
f(x) = One-half (one-half) superscript x
f(x) = 2(2)x

Answer 1

Use f(0)=0.5 to get the coefficient: a = 0.5.
Then f(1)=0.5·b = 1 ⇒ b = 2.

So f(x) = (1/2)·2^x, which is the second choice.