Question

On a coordinate plane, 2 exponential functions are shown. f (x) decreases from quadrant 2 to quadrant 1 and approaches y = 0. It crosses the y-axis at (0, 4) and goes through (1, 2). g (x) increases from quadrant 3 into quadrant 4 and approaches y = 0. It crosses the y-axis at (0, negative 4) and goes through (1, negative 2).
Which function represents g(x), a reflection of f(x) = 4(one-half) Superscript x across the x-axis?

g(x) = −4(2)x
g(x) = 4(2)−x
g(x) = −4(one-half) Superscript x
g(x) = 4(one-half) Superscript negative x

Answer 1

Reflection across the x-axis multiplies the function by −1, so

g(x) = −f(x) = −4(1/2)^x.

(This matches g(0) = −4 and g(1) = −2.)